31815747856 has 10 divisors (see below), whose sum is σ = 61643011502. Its totient is φ = 15907873920.

The previous prime is 31815747839. The next prime is 31815747871. The reversal of 31815747856 is 65874751813.

It can be written as a sum of positive squares in only one way, i.e., 31547443456 + 268304400 = 177616^2 + 16380^2 .

It is a junction number, because it is equal to n+sod(n) for n = 31815747797 and 31815747806.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994242105 + ... + 994242136.

Almost surely, 2^31815747856 is an apocalyptic number.

It is an amenable number.

31815747856 is a deficient number, since it is larger than the sum of its proper divisors (29827263646).

31815747856 is a wasteful number, since it uses less digits than its factorization.

31815747856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1988484249 (or 1988484243 counting only the distinct ones).

The product of its digits is 5644800, while the sum is 55.

The spelling of 31815747856 in words is "thirty-one billion, eight hundred fifteen million, seven hundred forty-seven thousand, eight hundred fifty-six".