251561140 has 24 divisors (see below), whose sum is σ = 556083360. Its totient is φ = 95328288.

The previous prime is 251561129. The next prime is 251561147. The reversal of 251561140 is 41165152.

It is a happy number.

251561140 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251561147) 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, 330622 + ... + 331381.

It is an arithmetic number, because the mean of its divisors is an integer number (23170140).

Almost surely, 2^251561140 is an apocalyptic number.

251561140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251561140 is an abundant number, since it is smaller than the sum of its proper divisors (304522220).

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

251561140 is a wasteful number, since it uses less digits than its factorization.

251561140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662031 (or 662029 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 251561140 is about 15860.6790522979. The cubic root of 251561140 is about 631.2690803630.

The spelling of 251561140 in words is "two hundred fifty-one million, five hundred sixty-one thousand, one hundred forty".