21017556131 has 32 divisors (see below), whose sum is σ = 25010366976. Its totient is φ = 17556132000.

The previous prime is 21017556113. The next prime is 21017556137. The reversal of 21017556131 is 13165571012.

It is not a de Polignac number, because 21017556131 - 2²² = 21013361827 is a prime.

It is a super-2 number, since 2×21017556131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21017556137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3925106 + ... + 3930456.

It is an arithmetic number, because the mean of its divisors is an integer number (781573968).

Almost surely, 2^21017556131 is an apocalyptic number.

21017556131 is a deficient number, since it is larger than the sum of its proper divisors (3992810845).

21017556131 is a wasteful number, since it uses less digits than its factorization.

21017556131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5624 (or 5602 counting only the distinct ones).

The product of its (nonzero) digits is 6300, while the sum is 32.

The spelling of 21017556131 in words is "twenty-one billion, seventeen million, five hundred fifty-six thousand, one hundred thirty-one".