31900 has 36 divisors (see below), whose sum is σ = 78120. Its totient is φ = 11200.

The previous prime is 31891. The next prime is 31907. The reversal of 31900 is 913.

It is a happy number.

31900 is nontrivially palindromic in base 9.

It is a super-2 number, since 2×31900² = 2035220000, which contains 22 as substring.

It is an Ulam number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31907) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1086 + ... + 1114.

It is an arithmetic number, because the mean of its divisors is an integer number (2170).

2³¹⁹⁰⁰ 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 31900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39060).

31900 is an abundant number, since it is smaller than the sum of its proper divisors (46220).

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

31900 is a wasteful number, since it uses less digits than its factorization.

31900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 27, while the sum is 13.

The square root of 31900 is about 178.6057109949. The cubic root of 31900 is about 31.7149156754.

Adding to 31900 its sum of digits (13), we get a palindrome (31913).

The spelling of 31900 in words is "thirty-one thousand, nine hundred".