251450561 has 4 divisors (see below), whose sum is σ = 260121300. Its totient is φ = 242779824.

The previous prime is 251450533. The next prime is 251450593. The reversal of 251450561 is 165054152.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 113529025 + 137921536 = 10655^2 + 11744^2 .

It is a cyclic number.

It is not a de Polignac number, because 251450561 - 2¹⁰ = 251449537 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 8670709 = 251450561 / (2 + 5 + 1 + 4 + 5 + 0 + 5 + 6 + 1).

It is not an unprimeable number, because it can be changed into a prime (251459561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4335326 + ... + 4335383.

It is an arithmetic number, because the mean of its divisors is an integer number (65030325).

Almost surely, 2^251450561 is an apocalyptic number.

It is an amenable number.

251450561 is a deficient number, since it is larger than the sum of its proper divisors (8670739).

251450561 is an equidigital number, since it uses as much as digits as its factorization.

251450561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8670738.

The product of its (nonzero) digits is 6000, while the sum is 29.

The square root of 251450561 is about 15857.1927212858. The cubic root of 251450561 is about 631.1765709314.

The spelling of 251450561 in words is "two hundred fifty-one million, four hundred fifty thousand, five hundred sixty-one".