664327491 has 4 divisors (see below), whose sum is σ = 885769992. Its totient is φ = 442884992.

The previous prime is 664327483. The next prime is 664327519. The reversal of 664327491 is 194723466.

664327491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 664327491 - 2³ = 664327483 is a prime.

It is not an unprimeable number, because it can be changed into a prime (664327691) 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, 110721246 + ... + 110721251.

It is an arithmetic number, because the mean of its divisors is an integer number (221442498).

Almost surely, 2^664327491 is an apocalyptic number.

664327491 is a deficient number, since it is larger than the sum of its proper divisors (221442501).

664327491 is a wasteful number, since it uses less digits than its factorization.

664327491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221442500.

The product of its digits is 217728, while the sum is 42.

The square root of 664327491 is about 25774.5512279070. The cubic root of 664327491 is about 872.5575383165.

The spelling of 664327491 in words is "six hundred sixty-four million, three hundred twenty-seven thousand, four hundred ninety-one".