251961120 has 144 divisors (see below), whose sum is σ = 883242360. Its totient is φ = 65359872.

The previous prime is 251961107. The next prime is 251961133. The reversal of 251961120 is 21169152.

251961120 is a `hidden beast` number, since 25 + 1 + 9 + 611 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (251961107) and next prime (251961133).

It can be written as a sum of positive squares in 4 ways, for example, as 181602576 + 70358544 = 13476^2 + 8388^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 50916 + ... + 55644.

Almost surely, 2^251961120 is an apocalyptic number.

251961120 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 251961120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (441621180).

251961120 is an abundant number, since it is smaller than the sum of its proper divisors (631281240).

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

251961120 is a wasteful number, since it uses less digits than its factorization.

251961120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4787 (or 4776 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 251961120 is about 15873.2832142566. The cubic root of 251961120 is about 631.6034739598.

The spelling of 251961120 in words is "two hundred fifty-one million, nine hundred sixty-one thousand, one hundred twenty".