251601798400 has 108 divisors (see below), whose sum is σ = 623653263324. Its totient is φ = 100495360000.

The previous prime is 251601798377. The next prime is 251601798403. The reversal of 251601798400 is 4897106152.

It can be written as a sum of positive squares in 6 ways, for example, as 7976633344 + 243625165056 = 89312^2 + 493584^2 .

It is a super-2 number, since 2×251601798400² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251601798403) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4458360 + ... + 4514440.

It is an arithmetic number, because the mean of its divisors is an integer number (5774567253).

Almost surely, 2^251601798400 is an apocalyptic number.

251601798400 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 251601798400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (311826631662).

251601798400 is an abundant number, since it is smaller than the sum of its proper divisors (372051464924).

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

251601798400 is an equidigital number, since it uses as much as digits as its factorization.

251601798400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56808 (or 56789 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 43.

The spelling of 251601798400 in words is "two hundred fifty-one billion, six hundred one million, seven hundred ninety-eight thousand, four hundred".