31890816400 has 45 divisors (see below), whose sum is σ = 76626268131. Its totient is φ = 12754897920.

The previous prime is 31890816389. The next prime is 31890816421. The reversal of 31890816400 is 461809813.

The square root of 31890816400 is 178580.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 14259225744 + 17631590656 = 119412^2 + 132784^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3567136 + ... + 3576064.

Almost surely, 2^31890816400 is an apocalyptic number.

31890816400 is the 178580-th square number.

It is an amenable number.

31890816400 is an abundant number, since it is smaller than the sum of its proper divisors (44735451731).

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

31890816400 is an frugal number, since it uses more digits than its factorization.

31890816400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17876 (or 8936 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 40.

The spelling of 31890816400 in words is "thirty-one billion, eight hundred ninety million, eight hundred sixteen thousand, four hundred".