655809091920 has 120 divisors (see below), whose sum is σ = 2238531020232. Its totient is φ = 172015488000.

The previous prime is 655809091901. The next prime is 655809091921. The reversal of 655809091920 is 29190908556.

It can be written as a sum of positive squares in 4 ways, for example, as 53422001424 + 602387090496 = 231132^2 + 776136^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (655809091921) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7422031 + ... + 7509870.

Almost surely, 2^655809091920 is an apocalyptic number.

655809091920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

655809091920 is an abundant number, since it is smaller than the sum of its proper divisors (1582721928312).

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

655809091920 is a wasteful number, since it uses less digits than its factorization.

655809091920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14931981 (or 14931972 counting only the distinct ones).

The product of its (nonzero) digits is 1749600, while the sum is 54.

The spelling of 655809091920 in words is "six hundred fifty-five billion, eight hundred nine million, ninety-one thousand, nine hundred twenty".