31724357661 has 12 divisors (see below), whose sum is σ = 46941733020. Its totient is φ = 20633728320.

The previous prime is 31724357647. The next prime is 31724357729. The reversal of 31724357661 is 16675342713.

31724357661 is a `hidden beast` number, since 3 + 1 + 72 + 4 + 3 + 576 + 6 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 17878364100 + 13845993561 = 133710^2 + 117669^2 .

It is not a de Polignac number, because 31724357661 - 2⁵ = 31724357629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31724356661) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42986566 + ... + 42987303.

It is an arithmetic number, because the mean of its divisors is an integer number (3911811085).

Almost surely, 2^31724357661 is an apocalyptic number.

It is an amenable number.

31724357661 is a deficient number, since it is larger than the sum of its proper divisors (15217375359).

31724357661 is a wasteful number, since it uses less digits than its factorization.

31724357661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85973916 (or 85973913 counting only the distinct ones).

The product of its digits is 635040, while the sum is 45.

The spelling of 31724357661 in words is "thirty-one billion, seven hundred twenty-four million, three hundred fifty-seven thousand, six hundred sixty-one".