251051040 has 144 divisors (see below), whose sum is σ = 860991768. Its totient is φ = 66613248.

The previous prime is 251051033. The next prime is 251051063. The reversal of 251051040 is 40150152.

It can be written as a sum of positive squares in 4 ways, for example, as 60279696 + 190771344 = 7764^2 + 13812^2 .

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

It is a Harshad number since it is a multiple of its sum of digits (18).

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, 450442 + ... + 450998.

Almost surely, 2^251051040 is an apocalyptic number.

251051040 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 251051040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (430495884).

251051040 is an abundant number, since it is smaller than the sum of its proper divisors (609940728).

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

251051040 is a wasteful number, since it uses less digits than its factorization.

251051040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 891 (or 880 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 251051040 is about 15844.5902439918. The cubic root of 251051040 is about 630.8421089394.

The spelling of 251051040 in words is "two hundred fifty-one million, fifty-one thousand, forty".