251520 has 64 divisors (see below), whose sum is σ = 807840. Its totient is φ = 66560.

The previous prime is 251519. The next prime is 251527. The reversal of 251520 is 25152.

It is a tau number, because it is divible by the number of its divisors (64).

It is a hoax number, since the sum of its digits (15) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a nialpdrome in base 8.

It is a zygodrome in base 4.

It is a self number, because there is not a number n which added to its sum of digits gives 251520.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251527) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1855 + ... + 1985.

2²⁵¹⁵²⁰ is an apocalyptic number.

251520 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 251520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (403920).

251520 is an abundant number, since it is smaller than the sum of its proper divisors (556320).

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

251520 is a wasteful number, since it uses less digits than its factorization.

251520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153 (or 141 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 15.

The square root of 251520 is about 501.5176965970. The cubic root of 251520 is about 63.1234666163.

Adding to 251520 its reverse (25152), we get a palindrome (276672).

The spelling of 251520 in words is "two hundred fifty-one thousand, five hundred twenty".