664505291 has 2 divisors, whose sum is σ = 664505292. Its totient is φ = 664505290.

The previous prime is 664505249. The next prime is 664505321. The reversal of 664505291 is 192505466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664505291 - 2¹⁴ = 664488907 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (664502291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332252645 + 332252646.

It is an arithmetic number, because the mean of its divisors is an integer number (332252646).

Almost surely, 2^664505291 is an apocalyptic number.

664505291 is a deficient number, since it is larger than the sum of its proper divisors (1).

664505291 is an equidigital number, since it uses as much as digits as its factorization.

664505291 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64800, while the sum is 38.

The square root of 664505291 is about 25778.0001357747. Note that the first 3 decimals coincide. The cubic root of 664505291 is about 872.6353748725.

The spelling of 664505291 in words is "six hundred sixty-four million, five hundred five thousand, two hundred ninety-one".