31217138 has 8 divisors (see below), whose sum is σ = 47485440. Its totient is φ = 15388660.

The previous prime is 31217111. The next prime is 31217149. The reversal of 31217138 is 83171213.

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

It is a super-2 number, since 2×31217138² = 1949019409822088, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 109778 + ... + 110061.

It is an arithmetic number, because the mean of its divisors is an integer number (5935680).

Almost surely, 2^31217138 is an apocalyptic number.

31217138 is the 2987-th centered heptagonal number.

31217138 is a deficient number, since it is larger than the sum of its proper divisors (16268302).

31217138 is a wasteful number, since it uses less digits than its factorization.

31217138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219912.

The product of its digits is 1008, while the sum is 26.

The square root of 31217138 is about 5587.2299039864. The cubic root of 31217138 is about 314.8698143481.

The spelling of 31217138 in words is "thirty-one million, two hundred seventeen thousand, one hundred thirty-eight".