31691120400 has 675 divisors, whose sum is σ = 121726322949. Its totient is φ = 7895543040.

The previous prime is 31691120389. The next prime is 31691120411. The reversal of 31691120400 is 402119613.

The square root of 31691120400 is 178020.

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

It is an interprime number because it is at equal distance from previous prime (31691120389) and next prime (31691120411).

It can be written as a sum of positive squares in only one way, i.e., 11408803344 + 20282317056 = 106812^2 + 142416^2 .

It is a tau number, because it is divible by the number of its divisors (675).

It is a super-2 number, since 2×31691120400² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 737002779 + ... + 737002821.

Almost surely, 2^31691120400 is an apocalyptic number.

31691120400 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

31691120400 is the 178020-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31691120400

31691120400 is an abundant number, since it is smaller than the sum of its proper divisors (90035202549).

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

31691120400 is a wasteful number, since it uses less digits than its factorization.

31691120400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162 (or 76 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

Multiplying 31691120400 by its product of nonzero digits (1296), we get a square (41071692038400 = 6408720²).

31691120400 divided by its product of nonzero digits (1296) gives a square (24453025 = 4945²).

It can be divided in two parts, 31 and 691120400, that added together give a triangular number (691120431 = T₃₇₁₇₈).

The spelling of 31691120400 in words is "thirty-one billion, six hundred ninety-one million, one hundred twenty thousand, four hundred".