251225520 has 160 divisors (see below), whose sum is σ = 958605312. Its totient is φ = 53001216.

The previous prime is 251225503. The next prime is 251225561. The reversal of 251225520 is 25522152.

It is a super-2 number, since 2×251225520² = 126228523798540800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16089 + ... + 27591.

Almost surely, 2^251225520 is an apocalyptic number.

251225520 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 251225520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (479302656).

251225520 is an abundant number, since it is smaller than the sum of its proper divisors (707379792).

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

251225520 is a wasteful number, since it uses less digits than its factorization.

251225520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11539 (or 11533 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 24.

The square root of 251225520 is about 15850.0952678525. The cubic root of 251225520 is about 630.9882197882.

Adding to 251225520 its reverse (25522152), we get a palindrome (276747672).

The spelling of 251225520 in words is "two hundred fifty-one million, two hundred twenty-five thousand, five hundred twenty".