31397973778 has 16 divisors (see below), whose sum is σ = 50173313760. Its totient is φ = 14684867136.

The previous prime is 31397973769. The next prime is 31397973821. The reversal of 31397973778 is 87737979313.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2827188 + ... + 2838271.

It is an arithmetic number, because the mean of its divisors is an integer number (3135832110).

Almost surely, 2^31397973778 is an apocalyptic number.

31397973778 is a deficient number, since it is larger than the sum of its proper divisors (18775339982).

31397973778 is a wasteful number, since it uses less digits than its factorization.

31397973778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5665641.

The product of its digits is 42007896, while the sum is 64.

The spelling of 31397973778 in words is "thirty-one billion, three hundred ninety-seven million, nine hundred seventy-three thousand, seven hundred seventy-eight".