31800787920 has 560 divisors, whose sum is σ = 127345867200. Its totient is φ = 7300730880.

The previous prime is 31800787903. The next prime is 31800787927. The reversal of 31800787920 is 2978700813.

It is a super-2 number, since 2×31800787920² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31800787927) by changing a digit.

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 111 ways as a sum of consecutive naturals, for example, 12187576 + ... + 12190184.

Almost surely, 2^31800787920 is an apocalyptic number.

31800787920 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 31800787920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (63672933600).

31800787920 is an abundant number, since it is smaller than the sum of its proper divisors (95545079280).

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

31800787920 is a wasteful number, since it uses less digits than its factorization.

31800787920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2670 (or 2649 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The spelling of 31800787920 in words is "thirty-one billion, eight hundred million, seven hundred eighty-seven thousand, nine hundred twenty".