31131002021 has 32 divisors (see below), whose sum is σ = 40371540480. Its totient is φ = 23372845056.

The previous prime is 31131002003. The next prime is 31131002051. The reversal of 31131002021 is 12020013113.

It is a cyclic number.

It is not a de Polignac number, because 31131002021 - 2¹⁸ = 31130739877 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31131001987 and 31131002005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31131002051) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 52436 + ... + 254973.

It is an arithmetic number, because the mean of its divisors is an integer number (1261610640).

Almost surely, 2^31131002021 is an apocalyptic number.

It is an amenable number.

31131002021 is a deficient number, since it is larger than the sum of its proper divisors (9240538459).

31131002021 is a wasteful number, since it uses less digits than its factorization.

31131002021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307493.

The product of its (nonzero) digits is 36, while the sum is 14.

Adding to 31131002021 its reverse (12020013113), we get a palindrome (43151015134).

The spelling of 31131002021 in words is "thirty-one billion, one hundred thirty-one million, two thousand, twenty-one".