644302623 has 16 divisors (see below), whose sum is σ = 870711296. Its totient is φ = 423753120.

The previous prime is 644302579. The next prime is 644302627. The reversal of 644302623 is 326203446.

It is a happy number.

It is not a de Polignac number, because 644302623 - 2¹² = 644298527 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 (644302627) 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 15 ways as a sum of consecutive naturals, for example, 64290 + ... + 73632.

It is an arithmetic number, because the mean of its divisors is an integer number (54419456).

Almost surely, 2^644302623 is an apocalyptic number.

644302623 is a deficient number, since it is larger than the sum of its proper divisors (226408673).

644302623 is a wasteful number, since it uses less digits than its factorization.

644302623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9654.

The product of its (nonzero) digits is 20736, while the sum is 30.

The square root of 644302623 is about 25383.1168889875. The cubic root of 644302623 is about 863.7007561198.

The spelling of 644302623 in words is "six hundred forty-four million, three hundred two thousand, six hundred twenty-three".