664752691 has 4 divisors (see below), whose sum is σ = 664828384. Its totient is φ = 664677000.

The previous prime is 664752629. The next prime is 664752709. The reversal of 664752691 is 196257466.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 664752691 - 2¹³ = 664744499 is a prime.

It is a super-2 number, since 2×664752691² = 883792280383482962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664752191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22635 + ... + 42916.

It is an arithmetic number, because the mean of its divisors is an integer number (166207096).

Almost surely, 2^664752691 is an apocalyptic number.

664752691 is a deficient number, since it is larger than the sum of its proper divisors (75693).

664752691 is a wasteful number, since it uses less digits than its factorization.

664752691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75692.

The product of its digits is 544320, while the sum is 46.

The square root of 664752691 is about 25782.7983547170. The cubic root of 664752691 is about 872.7436575341.

The spelling of 664752691 in words is "six hundred sixty-four million, seven hundred fifty-two thousand, six hundred ninety-one".