31321990 has 32 divisors (see below), whose sum is σ = 68226624. Its totient is φ = 10106880.

The previous prime is 31321987. The next prime is 31322023. The reversal of 31321990 is 9912313.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11971 + ... + 14350.

It is an arithmetic number, because the mean of its divisors is an integer number (2132082).

Almost surely, 2^31321990 is an apocalyptic number.

31321990 is an abundant number, since it is smaller than the sum of its proper divisors (36904634).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31321990 is a wasteful number, since it uses less digits than its factorization.

31321990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26352.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 31321990 is about 5596.6052210246. The cubic root of 31321990 is about 315.2219482234.

The spelling of 31321990 in words is "thirty-one million, three hundred twenty-one thousand, nine hundred ninety".