31000431021 has 24 divisors (see below), whose sum is σ = 49381926720. Its totient is φ = 16944328896.

The previous prime is 31000431013. The next prime is 31000431031. The reversal of 31000431021 is 12013400013.

It is not a de Polignac number, because 31000431021 - 2³ = 31000431013 is a prime.

It is a super-2 number, since 2×31000431021² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31000431031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1384176 + ... + 1406393.

It is an arithmetic number, because the mean of its divisors is an integer number (2057580280).

Almost surely, 2^31000431021 is an apocalyptic number.

It is an amenable number.

31000431021 is a deficient number, since it is larger than the sum of its proper divisors (18381495699).

31000431021 is a wasteful number, since it uses less digits than its factorization.

31000431021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2790625 (or 2790602 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 31000431021 its reverse (12013400013), we get a palindrome (43013831034).

The spelling of 31000431021 in words is "thirty-one billion, four hundred thirty-one thousand, twenty-one".