31131332021 has 16 divisors (see below), whose sum is σ = 33775170240. Its totient is φ = 28596862080.

The previous prime is 31131331967. The next prime is 31131332047. The reversal of 31131332021 is 12023313113.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31131332021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31131331984 and 31131332002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31131332051) 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, 4391 + ... + 249563.

It is an arithmetic number, because the mean of its divisors is an integer number (2110948140).

Almost surely, 2^31131332021 is an apocalyptic number.

It is an amenable number.

31131332021 is a deficient number, since it is larger than the sum of its proper divisors (2643838219).

31131332021 is a wasteful number, since it uses less digits than its factorization.

31131332021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245396.

The product of its (nonzero) digits is 324, while the sum is 20.

Adding to 31131332021 its reverse (12023313113), we get a palindrome (43154645134).

The spelling of 31131332021 in words is "thirty-one billion, one hundred thirty-one million, three hundred thirty-two thousand, twenty-one".