664909291 has 12 divisors (see below), whose sum is σ = 679956984. Its totient is φ = 650180000.

The previous prime is 664909279. The next prime is 664909367. The reversal of 664909291 is 192909466.

It is not a de Polignac number, because 664909291 - 2⁷ = 664909163 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664909241) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 873351 + ... + 874111.

It is an arithmetic number, because the mean of its divisors is an integer number (56663082).

Almost surely, 2^664909291 is an apocalyptic number.

664909291 is a deficient number, since it is larger than the sum of its proper divisors (15047693).

664909291 is an equidigital number, since it uses as much as digits as its factorization.

664909291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1130 (or 1071 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 46.

The square root of 664909291 is about 25785.8350844024. The cubic root of 664909291 is about 872.8121847362.

The spelling of 664909291 in words is "six hundred sixty-four million, nine hundred nine thousand, two hundred ninety-one".