31399900 has 72 divisors (see below), whose sum is σ = 80439296. Its totient is φ = 10411200.

The previous prime is 31399897. The next prime is 31399981. The reversal of 31399900 is 999313.

It is a happy number.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20977 + ... + 22423.

Almost surely, 2^31399900 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31399900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40219648).

31399900 is an abundant number, since it is smaller than the sum of its proper divisors (49039396).

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

31399900 is a wasteful number, since it uses less digits than its factorization.

31399900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1499 (or 1492 counting only the distinct ones).

The product of its (nonzero) digits is 6561, while the sum is 34.

The square root of 31399900 is about 5603.5613675590. The cubic root of 31399900 is about 315.4830917792.

The spelling of 31399900 in words is "thirty-one million, three hundred ninety-nine thousand, nine hundred".