31391117 has 8 divisors (see below), whose sum is σ = 32235000. Its totient is φ = 30551040.

The previous prime is 31391099. The next prime is 31391119. The reversal of 31391117 is 71119313.

It can be written as a sum of positive squares in 4 ways, for example, as 2725801 + 28665316 = 1651^2 + 5354^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31391117 - 2⁸ = 31390861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31391119) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24509 + ... + 25757.

It is an arithmetic number, because the mean of its divisors is an integer number (4029375).

Almost surely, 2^31391117 is an apocalyptic number.

It is an amenable number.

31391117 is a deficient number, since it is larger than the sum of its proper divisors (843883).

31391117 is a wasteful number, since it uses less digits than its factorization.

31391117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1903.

The product of its digits is 567, while the sum is 26.

The square root of 31391117 is about 5602.7776147193. Note that the first 3 decimals coincide. The cubic root of 31391117 is about 315.4536739956.

The spelling of 31391117 in words is "thirty-one million, three hundred ninety-one thousand, one hundred seventeen".