251664461 has 4 divisors (see below), whose sum is σ = 257019072. Its totient is φ = 246309852.

The previous prime is 251664451. The next prime is 251664487. The reversal of 251664461 is 164466152.

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 251664461 - 2¹⁰ = 251663437 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251664401) 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, 2677235 + ... + 2677328.

It is an arithmetic number, because the mean of its divisors is an integer number (64254768).

Almost surely, 2^251664461 is an apocalyptic number.

It is an amenable number.

251664461 is a deficient number, since it is larger than the sum of its proper divisors (5354611).

251664461 is an equidigital number, since it uses as much as digits as its factorization.

251664461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5354610.

The product of its digits is 34560, while the sum is 35.

The square root of 251664461 is about 15863.9358609394. The cubic root of 251664461 is about 631.3554933191.

The spelling of 251664461 in words is "two hundred fifty-one million, six hundred sixty-four thousand, four hundred sixty-one".