251560 has 32 divisors (see below), whose sum is σ = 597600. Its totient is φ = 95040.

The previous prime is 251543. The next prime is 251561. The reversal of 251560 is 65152.

251560 = T₆₄ + T₆₅ + ... + T₁₂₀.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is not an unprimeable number, because it can be changed into a prime (251561) by changing a digit.

251560 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 595 + ... + 925.

It is an arithmetic number, because the mean of its divisors is an integer number (18675).

2²⁵¹⁵⁶⁰ is an apocalyptic number.

251560 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 251560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (298800).

251560 is an abundant number, since it is smaller than the sum of its proper divisors (346040).

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

251560 is a wasteful number, since it uses less digits than its factorization.

251560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361 (or 357 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 251560 is about 501.5575739633. The cubic root of 251560 is about 63.1268126787.

The spelling of 251560 in words is "two hundred fifty-one thousand, five hundred sixty".