664246637 has 4 divisors (see below), whose sum is σ = 673345980. Its totient is φ = 655147296.

The previous prime is 664246633. The next prime is 664246697. The reversal of 664246637 is 736642466.

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

It can be written as a sum of positive squares in 2 ways, for example, as 402162916 + 262083721 = 20054^2 + 16189^2 .

It is a cyclic number.

It is not a de Polignac number, because 664246637 - 2² = 664246633 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664246633) 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, 4549562 + ... + 4549707.

It is an arithmetic number, because the mean of its divisors is an integer number (168336495).

Almost surely, 2^664246637 is an apocalyptic number.

It is an amenable number.

664246637 is a deficient number, since it is larger than the sum of its proper divisors (9099343).

664246637 is an equidigital number, since it uses as much as digits as its factorization.

664246637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9099342.

The product of its digits is 870912, while the sum is 44.

The square root of 664246637 is about 25772.9826950627. The cubic root of 664246637 is about 872.5221377897.

The spelling of 664246637 in words is "six hundred sixty-four million, two hundred forty-six thousand, six hundred thirty-seven".