251728560 has 240 divisors, whose sum is σ = 916441344. Its totient is φ = 64094976.

The previous prime is 251728559. The next prime is 251728573. The reversal of 251728560 is 65827152.

It is a happy number.

251728560 is a `hidden beast` number, since 2 + 517 + 2 + 85 + 60 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 446839 + ... + 447401.

Almost surely, 2^251728560 is an apocalyptic number.

251728560 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 251728560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (458220672).

251728560 is an abundant number, since it is smaller than the sum of its proper divisors (664712784).

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

251728560 is a wasteful number, since it uses less digits than its factorization.

251728560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 614 (or 596 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The square root of 251728560 is about 15865.9560064939. The cubic root of 251728560 is about 631.4090909019.

The spelling of 251728560 in words is "two hundred fifty-one million, seven hundred twenty-eight thousand, five hundred sixty".