31042563721 has 9 divisors (see below), whose sum is σ = 33616617429. Its totient is φ = 28652559936.

The previous prime is 31042563701. The next prime is 31042563743. The reversal of 31042563721 is 12736524013.

The square root of 31042563721 is 176189.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 256352121 + 30786211600 = 16011^2 + 175460^2 .

It is not a de Polignac number, because 31042563721 - 2⁷ = 31042563593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31042563701) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2283681 + ... + 2297233.

Almost surely, 2^31042563721 is an apocalyptic number.

31042563721 is the 176189-th square number.

31042563721 is the 88095-th centered octagonal number.

It is an amenable number.

31042563721 is a deficient number, since it is larger than the sum of its proper divisors (2574053708).

31042563721 is an frugal number, since it uses more digits than its factorization.

31042563721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27132 (or 13566 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 34.

The spelling of 31042563721 in words is "thirty-one billion, forty-two million, five hundred sixty-three thousand, seven hundred twenty-one".