31720028920 has 32 divisors (see below), whose sum is σ = 71397572400. Its totient is φ = 12683121408.

The previous prime is 31720028911. The next prime is 31720028959. The reversal of 31720028920 is 2982002713.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 46830 + ... + 256189.

Almost surely, 2^31720028920 is an apocalyptic number.

It is an amenable number.

31720028920 is an abundant number, since it is smaller than the sum of its proper divisors (39677543480).

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

31720028920 is a wasteful number, since it uses less digits than its factorization.

31720028920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305647 (or 305643 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 34.

The spelling of 31720028920 in words is "thirty-one billion, seven hundred twenty million, twenty-eight thousand, nine hundred twenty".