31971813081 has 16 divisors (see below), whose sum is σ = 45942914304. Its totient is φ = 19660103424.

The previous prime is 31971813073. The next prime is 31971813089. The reversal of 31971813081 is 18031817913.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (31971813073) and next prime (31971813089).

It is not a de Polignac number, because 31971813081 - 2³ = 31971813073 is a prime.

It is a super-2 number, since 2×31971813081² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (31971813089) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 257136 + ... + 360641.

It is an arithmetic number, because the mean of its divisors is an integer number (2871432144).

Almost surely, 2^31971813081 is an apocalyptic number.

It is an amenable number.

31971813081 is a deficient number, since it is larger than the sum of its proper divisors (13971101223).

31971813081 is a wasteful number, since it uses less digits than its factorization.

31971813081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619120.

The product of its (nonzero) digits is 36288, while the sum is 42.

The spelling of 31971813081 in words is "thirty-one billion, nine hundred seventy-one million, eight hundred thirteen thousand, eighty-one".