31981415957 has 2 divisors, whose sum is σ = 31981415958. Its totient is φ = 31981415956.

The previous prime is 31981415953. The next prime is 31981415959. The reversal of 31981415957 is 75951418913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31703226916 + 278189041 = 178054^2 + 16679^2 .

It is a cyclic number.

It is not a de Polignac number, because 31981415957 - 2² = 31981415953 is a prime.

It is a super-2 number, since 2×31981415957² (a number of 22 digits) contains 22 as substring.

Together with 31981415959, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 31981415899 and 31981415908.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31981415951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15990707978 + 15990707979.

It is an arithmetic number, because the mean of its divisors is an integer number (15990707979).

Almost surely, 2^31981415957 is an apocalyptic number.

It is an amenable number.

31981415957 is a deficient number, since it is larger than the sum of its proper divisors (1).

31981415957 is an equidigital number, since it uses as much as digits as its factorization.

31981415957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1360800, while the sum is 53.

The spelling of 31981415957 in words is "thirty-one billion, nine hundred eighty-one million, four hundred fifteen thousand, nine hundred fifty-seven".