644377445 has 16 divisors (see below), whose sum is σ = 793638000. Its totient is φ = 502055424.

The previous prime is 644377441. The next prime is 644377463. The reversal of 644377445 is 544773446.

644377445 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 21325924 + 623051521 = 4618^2 + 24961^2 .

It is a cyclic number.

It is not a de Polignac number, because 644377445 - 2² = 644377441 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644377396 and 644377405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644377441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27431 + ... + 45179.

It is an arithmetic number, because the mean of its divisors is an integer number (49602375).

Almost surely, 2^644377445 is an apocalyptic number.

It is an amenable number.

644377445 is a deficient number, since it is larger than the sum of its proper divisors (149260555).

644377445 is a wasteful number, since it uses less digits than its factorization.

644377445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17944.

The product of its digits is 1128960, while the sum is 44.

The square root of 644377445 is about 25384.5906998714. The cubic root of 644377445 is about 863.7341882961.

The spelling of 644377445 in words is "six hundred forty-four million, three hundred seventy-seven thousand, four hundred forty-five".