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21097440 = 25325721323
BaseRepresentation
bin101000001111…
…0101111100000
31110200212020200
41100132233200
520400104230
62032105200
7344216400
oct120365740
943625220
1021097440
11109aa901
127095200
1344a8ac0
142b32800
151cbb160
hex141ebe0

21097440 has 432 divisors, whose sum is σ = 94112928. Its totient is φ = 4257792.

The previous prime is 21097423. The next prime is 21097441. The reversal of 21097440 is 4479012.

It is a happy number.

21097440 is a `hidden beast` number, since 210 + 9 + 7 + 440 = 666.

21097440 is nontrivially palindromic in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21097441) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 917269 + ... + 917291.

It is an arithmetic number, because the mean of its divisors is an integer number (217854).

Almost surely, 221097440 is an apocalyptic number.

21097440 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 21097440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47056464).

21097440 is an abundant number, since it is smaller than the sum of its proper divisors (73015488).

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

21097440 is a wasteful number, since it uses less digits than its factorization.

21097440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21097440 is about 4593.1949664694. The cubic root of 21097440 is about 276.3184729564.

The spelling of 21097440 in words is "twenty-one million, ninety-seven thousand, four hundred forty".