251315261 has 4 divisors (see below), whose sum is σ = 264542400. Its totient is φ = 238088124.

The previous prime is 251315243. The next prime is 251315269. The reversal of 251315261 is 162513152.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 251315261 - 2¹⁰ = 251314237 is a prime.

It is a super-2 number, since 2×251315261² = 126318720822996242, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 251315261.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251315269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6613541 + ... + 6613578.

It is an arithmetic number, because the mean of its divisors is an integer number (66135600).

Almost surely, 2^251315261 is an apocalyptic number.

It is an amenable number.

251315261 is a deficient number, since it is larger than the sum of its proper divisors (13227139).

251315261 is a wasteful number, since it uses less digits than its factorization.

251315261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13227138.

The product of its digits is 1800, while the sum is 26.

The square root of 251315261 is about 15852.9259444432. The cubic root of 251315261 is about 631.0633432241.

The spelling of 251315261 in words is "two hundred fifty-one million, three hundred fifteen thousand, two hundred sixty-one".