21220031131 has 16 divisors (see below), whose sum is σ = 23164848000. Its totient is φ = 19320357888.

The previous prime is 21220031113. The next prime is 21220031137. The reversal of 21220031131 is 13113002212.

It is not a de Polignac number, because 21220031131 - 2²⁹ = 20683160219 is a prime.

It is a super-2 number, since 2×21220031131² (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 (21220031137) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1067475 + ... + 1087171.

It is an arithmetic number, because the mean of its divisors is an integer number (1447803000).

Almost surely, 2^21220031131 is an apocalyptic number.

21220031131 is a deficient number, since it is larger than the sum of its proper divisors (1944816869).

21220031131 is a wasteful number, since it uses less digits than its factorization.

21220031131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20838.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21220031131 its reverse (13113002212), we get a palindrome (34333033343).

The spelling of 21220031131 in words is "twenty-one billion, two hundred twenty million, thirty-one thousand, one hundred thirty-one".