255540391920 has 640 divisors, whose sum is σ = 1021614612480. Its totient is φ = 58023198720.

The previous prime is 255540391907. The next prime is 255540391927. The reversal of 255540391920 is 29193045552.

255540391920 is a `hidden beast` number, since 2 + 5 + 55 + 403 + 9 + 192 + 0 = 666.

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 (255540391927) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 90072742 + ... + 90075578.

It is an arithmetic number, because the mean of its divisors is an integer number (1596272832).

Almost surely, 2^255540391920 is an apocalyptic number.

255540391920 is a gapful number since it is divisible by the number (20) 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 255540391920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (510807306240).

255540391920 is an abundant number, since it is smaller than the sum of its proper divisors (766074220560).

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

255540391920 is a wasteful number, since it uses less digits than its factorization.

255540391920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3110 (or 3098 counting only the distinct ones).

The product of its (nonzero) digits is 486000, while the sum is 45.

The spelling of 255540391920 in words is "two hundred fifty-five billion, five hundred forty million, three hundred ninety-one thousand, nine hundred twenty".