31686621 has 8 divisors (see below), whose sum is σ = 42275904. Its totient is φ = 21110880.

The previous prime is 31686587. The next prime is 31686631. The reversal of 31686621 is 12668613.

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

It is not a de Polignac number, because 31686621 - 2¹⁷ = 31555549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31686631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5160 + ... + 9486.

It is an arithmetic number, because the mean of its divisors is an integer number (5284488).

Almost surely, 2^31686621 is an apocalyptic number.

It is an amenable number.

31686621 is a deficient number, since it is larger than the sum of its proper divisors (10589283).

31686621 is a wasteful number, since it uses less digits than its factorization.

31686621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6771.

The product of its digits is 10368, while the sum is 33.

The square root of 31686621 is about 5629.0870485364. The cubic root of 31686621 is about 316.4404376185.

The spelling of 31686621 in words is "thirty-one million, six hundred eighty-six thousand, six hundred twenty-one".