644749448 has 32 divisors (see below), whose sum is σ = 1409808000. Its totient is φ = 276320016.

The previous prime is 644749393. The next prime is 644749459. The reversal of 644749448 is 844947446.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 644749396 and 644749405.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114740 + ... + 120227.

It is an arithmetic number, because the mean of its divisors is an integer number (44056500).

Almost surely, 2^644749448 is an apocalyptic number.

It is an amenable number.

644749448 is an abundant number, since it is smaller than the sum of its proper divisors (765058552).

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

644749448 is a wasteful number, since it uses less digits than its factorization.

644749448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234994 (or 234976 counting only the distinct ones).

The product of its digits is 3096576, while the sum is 50.

The square root of 644749448 is about 25391.9169815908. The cubic root of 644749448 is about 863.9003693130.

The spelling of 644749448 in words is "six hundred forty-four million, seven hundred forty-nine thousand, four hundred forty-eight".