644959448 has 16 divisors (see below), whose sum is σ = 1382056080. Its totient is φ = 276411168.

The previous prime is 644959429. The next prime is 644959459. The reversal of 644959448 is 844959446.

It is a self number, because there is not a number n which added to its sum of digits gives 644959448.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5758511 + ... + 5758622.

It is an arithmetic number, because the mean of its divisors is an integer number (86378505).

Almost surely, 2^644959448 is an apocalyptic number.

It is an amenable number.

644959448 is an abundant number, since it is smaller than the sum of its proper divisors (737096632).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644959448 is a wasteful number, since it uses less digits than its factorization.

644959448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11517146 (or 11517142 counting only the distinct ones).

The product of its digits is 4976640, while the sum is 53.

The square root of 644959448 is about 25396.0518191313. The cubic root of 644959448 is about 863.9941521952.

The spelling of 644959448 in words is "six hundred forty-four million, nine hundred fifty-nine thousand, four hundred forty-eight".