21221320131 has 36 divisors (see below), whose sum is σ = 33723425736. Its totient is φ = 12849788160.

The previous prime is 21221320123. The next prime is 21221320163. The reversal of 21221320131 is 13102312212.

21221320131 is a `hidden beast` number, since 212 + 2 + 1 + 320 + 131 = 666.

It is not a de Polignac number, because 21221320131 - 2³ = 21221320123 is a prime.

It is a super-2 number, since 2×21221320131² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21221320171) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1284435 + ... + 1300851.

It is an arithmetic number, because the mean of its divisors is an integer number (936761826).

Almost surely, 2^21221320131 is an apocalyptic number.

21221320131 is a deficient number, since it is larger than the sum of its proper divisors (12502105605).

21221320131 is a wasteful number, since it uses less digits than its factorization.

21221320131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17632 (or 17618 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21221320131 its reverse (13102312212), we get a palindrome (34323632343).

The spelling of 21221320131 in words is "twenty-one billion, two hundred twenty-one million, three hundred twenty thousand, one hundred thirty-one".