31890989520 has 720 divisors, whose sum is σ = 127565710272. Its totient is φ = 7375380480.

The previous prime is 31890989519. The next prime is 31890989539. The reversal of 31890989520 is 2598909813.

31890989520 is a `hidden beast` number, since 31 + 8 + 9 + 0 + 9 + 89 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

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 143 ways as a sum of consecutive naturals, for example, 55850835 + ... + 55851405.

Almost surely, 2^31890989520 is an apocalyptic number.

31890989520 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 31890989520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (63782855136).

31890989520 is an abundant number, since it is smaller than the sum of its proper divisors (95674720752).

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

31890989520 is a wasteful number, since it uses less digits than its factorization.

31890989520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 642 (or 611 counting only the distinct ones).

The product of its (nonzero) digits is 1399680, while the sum is 54.

The spelling of 31890989520 in words is "thirty-one billion, eight hundred ninety million, nine hundred eighty-nine thousand, five hundred twenty".