644310623 has 4 divisors (see below), whose sum is σ = 702884328. Its totient is φ = 585736920.

The previous prime is 644310617. The next prime is 644310677. The reversal of 644310623 is 326013446.

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 644310623 - 2⁴ = 644310607 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 (644312623) 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, 29286836 + ... + 29286857.

It is an arithmetic number, because the mean of its divisors is an integer number (175721082).

Almost surely, 2^644310623 is an apocalyptic number.

644310623 is a deficient number, since it is larger than the sum of its proper divisors (58573705).

644310623 is a wasteful number, since it uses less digits than its factorization.

644310623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58573704.

The product of its (nonzero) digits is 10368, while the sum is 29.

The square root of 644310623 is about 25383.2744735584. The cubic root of 644310623 is about 863.7043308259.

The spelling of 644310623 in words is "six hundred forty-four million, three hundred ten thousand, six hundred twenty-three".