31890385 has 16 divisors (see below), whose sum is σ = 41212800. Its totient is φ = 23600896.

The previous prime is 31890371. The next prime is 31890389. The reversal of 31890385 is 58309813.

31890385 = 706² + 707² + ... + 764².

It is not a de Polignac number, because 31890385 - 2⁹ = 31889873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (31890389) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1836 + ... + 8194.

It is an arithmetic number, because the mean of its divisors is an integer number (2575800).

Almost surely, 2^31890385 is an apocalyptic number.

It is an amenable number.

31890385 is a deficient number, since it is larger than the sum of its proper divisors (9322415).

31890385 is a wasteful number, since it uses less digits than its factorization.

31890385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6440.

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 31890385 is about 5647.1572494486. The cubic root of 31890385 is about 317.1172895065.

The spelling of 31890385 in words is "thirty-one million, eight hundred ninety thousand, three hundred eighty-five".