21625531431 has 32 divisors (see below), whose sum is σ = 34740507648. Its totient is φ = 11698283520.

The previous prime is 21625531427. The next prime is 21625531453. The reversal of 21625531431 is 13413552612.

It is not a de Polignac number, because 21625531431 - 2² = 21625531427 is a prime.

It is a super-2 number, since 2×21625531431² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21625531392 and 21625531401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21625531231) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 183940 + ... + 277641.

It is an arithmetic number, because the mean of its divisors is an integer number (1085640864).

Almost surely, 2^21625531431 is an apocalyptic number.

21625531431 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21625531431 is a deficient number, since it is larger than the sum of its proper divisors (13114976217).

21625531431 is a wasteful number, since it uses less digits than its factorization.

21625531431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461711.

The product of its digits is 21600, while the sum is 33.

The spelling of 21625531431 in words is "twenty-one billion, six hundred twenty-five million, five hundred thirty-one thousand, four hundred thirty-one".