251281085 has 16 divisors (see below), whose sum is σ = 340295040. Its totient is φ = 176447040.

The previous prime is 251281039. The next prime is 251281117. The reversal of 251281085 is 580182152.

It is a happy number.

It is not a de Polignac number, because 251281085 - 2¹⁴ = 251264701 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 77177 + ... + 80366.

It is an arithmetic number, because the mean of its divisors is an integer number (21268440).

Almost surely, 2^251281085 is an apocalyptic number.

It is an amenable number.

251281085 is a deficient number, since it is larger than the sum of its proper divisors (89013955).

251281085 is a wasteful number, since it uses less digits than its factorization.

251281085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157588.

The product of its (nonzero) digits is 6400, while the sum is 32.

The square root of 251281085 is about 15851.8479995236. The cubic root of 251281085 is about 631.0347361292.

The spelling of 251281085 in words is "two hundred fifty-one million, two hundred eighty-one thousand, eighty-five".