31497968891 has 2 divisors, whose sum is σ = 31497968892. Its totient is φ = 31497968890.

The previous prime is 31497968867. The next prime is 31497968921. The reversal of 31497968891 is 19886979413.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31497968891 - 2³⁴ = 14318099707 is a prime.

It is not a weakly prime, because it can be changed into another prime (31497968851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15748984445 + 15748984446.

It is an arithmetic number, because the mean of its divisors is an integer number (15748984446).

Almost surely, 2^31497968891 is an apocalyptic number.

31497968891 is a deficient number, since it is larger than the sum of its proper divisors (1).

31497968891 is an equidigital number, since it uses as much as digits as its factorization.

31497968891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23514624, while the sum is 65.

The spelling of 31497968891 in words is "thirty-one billion, four hundred ninety-seven million, nine hundred sixty-eight thousand, eight hundred ninety-one".