664642623 has 8 divisors (see below), whose sum is σ = 894794368. Its totient is φ = 438792984.

The previous prime is 664642597. The next prime is 664642633. The reversal of 664642623 is 326246466.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 664642623 - 2¹⁰ = 664641599 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 (664642633) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1075165 + ... + 1075782.

It is an arithmetic number, because the mean of its divisors is an integer number (111849296).

Almost surely, 2^664642623 is an apocalyptic number.

664642623 is a deficient number, since it is larger than the sum of its proper divisors (230151745).

664642623 is a wasteful number, since it uses less digits than its factorization.

664642623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2151053.

The product of its digits is 248832, while the sum is 39.

The square root of 664642623 is about 25780.6637424253. The cubic root of 664642623 is about 872.6954860098.

The spelling of 664642623 in words is "six hundred sixty-four million, six hundred forty-two thousand, six hundred twenty-three".