21255231025031 has 4 divisors (see below), whose sum is σ = 21465678857064. Its totient is φ = 21044783193000.

The previous prime is 21255231025009. The next prime is 21255231025033. The reversal of 21255231025031 is 13052013255212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21255231025031 is a prime.

It is a super-2 number, since 2×21255231025031² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255231025033) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105223915865 + ... + 105223916066.

It is an arithmetic number, because the mean of its divisors is an integer number (5366419714266).

Almost surely, 2^{21255231025031} is an apocalyptic number.

21255231025031 is a deficient number, since it is larger than the sum of its proper divisors (210447832033).

21255231025031 is a wasteful number, since it uses less digits than its factorization.

21255231025031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210447832032.

The product of its (nonzero) digits is 18000, while the sum is 32.

The spelling of 21255231025031 in words is "twenty-one trillion, two hundred fifty-five billion, two hundred thirty-one million, twenty-five thousand, thirty-one".