251312985 has 192 divisors, whose sum is σ = 584962560. Its totient is φ = 96768000.

The previous prime is 251312953. The next prime is 251312987. The reversal of 251312985 is 589213152.

251312985 is a `hidden beast` number, since 251 + 312 + 98 + 5 = 666.

It is not a de Polignac number, because 251312985 - 2⁵ = 251312953 is a prime.

It is a super-2 number, since 2×251312985² = 126316432859220450, which contains 22 as substring.

Its product of digits (21600) is a multiple of the sum of its prime factors (160).

It is not an unprimeable number, because it can be changed into a prime (251312987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 4119855 + ... + 4119915.

It is an arithmetic number, because the mean of its divisors is an integer number (3046680).

Almost surely, 2^251312985 is an apocalyptic number.

It is an amenable number.

251312985 is an abundant number, since it is smaller than the sum of its proper divisors (333649575).

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

251312985 is a wasteful number, since it uses less digits than its factorization.

251312985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160 (or 157 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The square root of 251312985 is about 15852.8541594250. The cubic root of 251312985 is about 631.0614381740.

It can be divided in two parts, 251 and 312985, that added together give a triangular number (313236 = T₇₉₁).

The spelling of 251312985 in words is "two hundred fifty-one million, three hundred twelve thousand, nine hundred eighty-five".