21131231331 has 24 divisors (see below), whose sum is σ = 32783843664. Its totient is φ = 12071720640.

The previous prime is 21131231323. The next prime is 21131231377. The reversal of 21131231331 is 13313213112.

It is a happy number.

It is not a de Polignac number, because 21131231331 - 2³ = 21131231323 is a prime.

It is a super-2 number, since 2×21131231331² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 21131231298 and 21131231307.

It is not an unprimeable number, because it can be changed into a prime (21131281331) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 590161 + ... + 624941.

It is an arithmetic number, because the mean of its divisors is an integer number (1365993486).

Almost surely, 2^21131231331 is an apocalyptic number.

21131231331 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21131231331 is a deficient number, since it is larger than the sum of its proper divisors (11652612333).

21131231331 is a wasteful number, since it uses less digits than its factorization.

21131231331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38931 (or 38924 counting only the distinct ones).

The product of its digits is 324, while the sum is 21.

Adding to 21131231331 its reverse (13313213112), we get a palindrome (34444444443).

The spelling of 21131231331 in words is "twenty-one billion, one hundred thirty-one million, two hundred thirty-one thousand, three hundred thirty-one".