31781308856 has 16 divisors (see below), whose sum is σ = 65007222840. Its totient is φ = 14446049440.

The previous prime is 31781308849. The next prime is 31781308879. The reversal of 31781308856 is 65880318713.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 180575531 + ... + 180575706.

Almost surely, 2^31781308856 is an apocalyptic number.

It is an amenable number.

31781308856 is an abundant number, since it is smaller than the sum of its proper divisors (33225913984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31781308856 is a wasteful number, since it uses less digits than its factorization.

31781308856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361151254 (or 361151250 counting only the distinct ones).

The product of its (nonzero) digits is 967680, while the sum is 50.

The spelling of 31781308856 in words is "thirty-one billion, seven hundred eighty-one million, three hundred eight thousand, eight hundred fifty-six".