664605251 has 2 divisors, whose sum is σ = 664605252. Its totient is φ = 664605250.

The previous prime is 664605241. The next prime is 664605257. The reversal of 664605251 is 152506466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664605251 - 2¹⁴ = 664588867 is a prime.

It is not a weakly prime, because it can be changed into another prime (664605257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332302625 + 332302626.

It is an arithmetic number, because the mean of its divisors is an integer number (332302626).

Almost surely, 2^664605251 is an apocalyptic number.

664605251 is a deficient number, since it is larger than the sum of its proper divisors (1).

664605251 is an equidigital number, since it uses as much as digits as its factorization.

664605251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 664605251 is about 25779.9389254513. The cubic root of 664605251 is about 872.6791288549.

The spelling of 664605251 in words is "six hundred sixty-four million, six hundred five thousand, two hundred fifty-one".