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21816531152640 = 2833571731211811
BaseRepresentation
bin1001111010111100011101…
…00101101110111100000000
32212020122021120022020101000
410331132032211232330000
510324420223433341030
6114222213121012000
74411122660036150
oct475361645567400
985218246266330
1021816531152640
116a51380097344
122544234184000
13c233a0353a63
14555cd6342760
1527c770d53860
hex13d78e96ef00

21816531152640 has 2304 divisors, whose sum is σ = 97282898657280. Its totient is φ = 4514807808000.

The previous prime is 21816531152639. The next prime is 21816531152641. The reversal of 21816531152640 is 4625113561812.

21816531152640 is a `hidden beast` number, since 2 + 1 + 8 + 1 + 6 + 531 + 1 + 52 + 64 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21816531152639) and next prime (21816531152641).

It is a tau number, because it is divible by the number of its divisors (2304).

It is a super-2 number, since 2×218165311526402 (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21816531152641) by changing a digit.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 26900777835 + ... + 26900778645.

It is an arithmetic number, because the mean of its divisors is an integer number (42223480320).

Almost surely, 221816531152640 is an apocalyptic number.

21816531152640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21816531152640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48641449328640).

21816531152640 is an abundant number, since it is smaller than the sum of its proper divisors (75466367504640).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21816531152640 is a wasteful number, since it uses less digits than its factorization.

21816531152640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1107 (or 1087 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The spelling of 21816531152640 in words is "twenty-one trillion, eight hundred sixteen billion, five hundred thirty-one million, one hundred fifty-two thousand, six hundred forty".