31400 has 24 divisors (see below), whose sum is σ = 73470. Its totient is φ = 12480.

The previous prime is 31397. The next prime is 31469. The reversal of 31400 is 413.

It can be written as a sum of positive squares in 3 ways, for example, as 20164 + 11236 = 142^2 + 106^2 .

It is a Harshad number since it is a multiple of its sum of digits (8).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 122 + ... + 278.

2³¹⁴⁰⁰ 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 31400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36735).

31400 is an abundant number, since it is smaller than the sum of its proper divisors (42070).

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

31400 is a wasteful number, since it uses less digits than its factorization.

31400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173 (or 164 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 8.

The square root of 31400 is about 177.2004514667. The cubic root of 31400 is about 31.5483426688.

Adding to 31400 its reverse (413), we get a palindrome (31813).

The spelling of 31400 in words is "thirty-one thousand, four hundred".