255638021760 has 448 divisors, whose sum is σ = 999601313760. Its totient is φ = 61971609600.

The previous prime is 255638021759. The next prime is 255638021773. The reversal of 255638021760 is 67120836552.

255638021760 is a `hidden beast` number, since 2 + 5 + 5 + 638 + 0 + 2 + 1 + 7 + 6 + 0 = 666.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 5107255 + ... + 5157065.

Almost surely, 2^255638021760 is an apocalyptic number.

255638021760 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 255638021760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (499800656880).

255638021760 is an abundant number, since it is smaller than the sum of its proper divisors (743963292000).

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

255638021760 is an equidigital number, since it uses as much as digits as its factorization.

255638021760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49859 (or 49832 counting only the distinct ones).

The product of its (nonzero) digits is 604800, while the sum is 45.

The spelling of 255638021760 in words is "two hundred fifty-five billion, six hundred thirty-eight million, twenty-one thousand, seven hundred sixty".