31661744400 has 1440 divisors, whose sum is σ = 141815923200. Its totient is φ = 6631372800.

The previous prime is 31661744399. The next prime is 31661744423. The reversal of 31661744400 is 444716613.

31661744400 is a `hidden beast` number, since 31 + 6 + 617 + 4 + 4 + 4 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 381466759 + ... + 381466841.

It is an arithmetic number, because the mean of its divisors is an integer number (98483280).

Almost surely, 2^31661744400 is an apocalyptic number.

31661744400 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31661744400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (70907961600).

31661744400 is an abundant number, since it is smaller than the sum of its proper divisors (110154178800).

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

31661744400 is a wasteful number, since it uses less digits than its factorization.

31661744400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166 (or 136 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

It can be divided in two parts, 316 and 61744400, that added together give a palindrome (61744716).

The spelling of 31661744400 in words is "thirty-one billion, six hundred sixty-one million, seven hundred forty-four thousand, four hundred".