21131023131 has 12 divisors (see below), whose sum is σ = 30539788552. Its totient is φ = 14079410496.

The previous prime is 21131023057. The next prime is 21131023141. The reversal of 21131023131 is 13132013112.

It is not a de Polignac number, because 21131023131 - 2²⁵ = 21097468699 is a prime.

It is a super-2 number, since 2×21131023131² (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 (21131023141) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 644641 + ... + 676626.

Almost surely, 2^21131023131 is an apocalyptic number.

21131023131 is a deficient number, since it is larger than the sum of its proper divisors (9408765421).

21131023131 is a wasteful number, since it uses less digits than its factorization.

21131023131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1323050 (or 1323047 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

Adding to 21131023131 its reverse (13132013112), we get a palindrome (34263036243).

The spelling of 21131023131 in words is "twenty-one billion, one hundred thirty-one million, twenty-three thousand, one hundred thirty-one".