31917913 has 4 divisors (see below), whose sum is σ = 32045328. Its totient is φ = 31790500.

The previous prime is 31917901. The next prime is 31917917. The reversal of 31917913 is 31971913.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31971913 = 683 ⋅46811.

It is a cyclic number.

It is not a de Polignac number, because 31917913 - 2²¹ = 29820761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31917917) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63331 + ... + 63832.

It is an arithmetic number, because the mean of its divisors is an integer number (8011332).

Almost surely, 2^31917913 is an apocalyptic number.

It is an amenable number.

31917913 is a deficient number, since it is larger than the sum of its proper divisors (127415).

31917913 is a wasteful number, since it uses less digits than its factorization.

31917913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127414.

The product of its digits is 5103, while the sum is 34.

The square root of 31917913 is about 5649.5940562132. The cubic root of 31917913 is about 317.2085092072.

The spelling of 31917913 in words is "thirty-one million, nine hundred seventeen thousand, nine hundred thirteen".