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81490080 = 2535779307
BaseRepresentation
bin1001101101101…
…11000010100000
312200100010101010
410312313002200
5131330140310
612030340520
72006440260
oct466670240
9180303333
1081490080
1141aa9781
122335a740
1313b626a9
14ab737a0
15724a320
hex4db70a0

81490080 has 192 divisors, whose sum is σ = 298045440. Its totient is φ = 18330624.

The previous prime is 81490067. The next prime is 81490109. The reversal of 81490080 is 8009418.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 265287 + ... + 265593.

It is an arithmetic number, because the mean of its divisors is an integer number (1552320).

Almost surely, 281490080 is an apocalyptic number.

81490080 is a gapful number since it is divisible by the number (80) 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 81490080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149022720).

81490080 is an abundant number, since it is smaller than the sum of its proper divisors (216555360).

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

81490080 is a wasteful number, since it uses less digits than its factorization.

81490080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411 (or 403 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 81490080 is about 9027.1856079290. The cubic root of 81490080 is about 433.5457315106.

Adding to 81490080 its reverse (8009418), we get a palindrome (89499498).

The spelling of 81490080 in words is "eighty-one million, four hundred ninety thousand, eighty".