664262491 has 2 divisors, whose sum is σ = 664262492. Its totient is φ = 664262490.

The previous prime is 664262483. The next prime is 664262497. The reversal of 664262491 is 194262466.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664262491 - 2³ = 664262483 is a prime.

It is not a weakly prime, because it can be changed into another prime (664262497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332131245 + 332131246.

It is an arithmetic number, because the mean of its divisors is an integer number (332131246).

Almost surely, 2^664262491 is an apocalyptic number.

664262491 is a deficient number, since it is larger than the sum of its proper divisors (1).

664262491 is an equidigital number, since it uses as much as digits as its factorization.

664262491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 124416, while the sum is 40.

The square root of 664262491 is about 25773.2902633715. The cubic root of 664262491 is about 872.5290794160.

The spelling of 664262491 in words is "six hundred sixty-four million, two hundred sixty-two thousand, four hundred ninety-one".