21656060657028 has 108 divisors (see below), whose sum is σ = 63782008158960. Its totient is φ = 6177449716704.

The previous prime is 21656060656999. The next prime is 21656060657029. The reversal of 21656060657028 is 82075606065612.

21656060657028 is a `hidden beast` number, since 2 + 1 + 6 + 5 + 6 + 0 + 60 + 6 + 570 + 2 + 8 = 666.

It is a super-2 number, since 2×21656060657028² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21656060657029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 8824626 + ... + 11008457.

It is an arithmetic number, because the mean of its divisors is an integer number (590574149620).

Almost surely, 2^{21656060657028} is an apocalyptic number.

21656060657028 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21656060657028 is an abundant number, since it is smaller than the sum of its proper divisors (42125947501932).

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

21656060657028 is a wasteful number, since it uses less digits than its factorization.

21656060657028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19833726 (or 19833714 counting only the distinct ones).

The product of its (nonzero) digits is 7257600, while the sum is 54.

The spelling of 21656060657028 in words is "twenty-one trillion, six hundred fifty-six billion, sixty million, six hundred fifty-seven thousand, twenty-eight".