644514432 has 32 divisors (see below), whose sum is σ = 1711992480. Its totient is φ = 214838016.

The previous prime is 644514427. The next prime is 644514449. The reversal of 644514432 is 234415446.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

It is a junction number, because it is equal to n+sod(n) for n = 644514393 and 644514402.

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, 838828 + ... + 839595.

It is an arithmetic number, because the mean of its divisors is an integer number (53499765).

Almost surely, 2^644514432 is an apocalyptic number.

It is an amenable number.

644514432 is an abundant number, since it is smaller than the sum of its proper divisors (1067478048).

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

644514432 is a wasteful number, since it uses less digits than its factorization.

644514432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1678440 (or 1678428 counting only the distinct ones).

The product of its digits is 46080, while the sum is 33.

The square root of 644514432 is about 25387.2887878954. The cubic root of 644514432 is about 863.7953905064.

Adding to 644514432 its reverse (234415446), we get a palindrome (878929878).

The spelling of 644514432 in words is "six hundred forty-four million, five hundred fourteen thousand, four hundred thirty-two".