644418892 has 12 divisors (see below), whose sum is σ = 1214481856. Its totient is φ = 297424080.

The previous prime is 644418883. The next prime is 644418893. The reversal of 644418892 is 298814446.

It is not an unprimeable number, because it can be changed into a prime (644418893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6196284 + ... + 6196387.

Almost surely, 2^644418892 is an apocalyptic number.

It is an amenable number.

644418892 is a deficient number, since it is larger than the sum of its proper divisors (570062964).

644418892 is a wasteful number, since it uses less digits than its factorization.

644418892 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12392688 (or 12392686 counting only the distinct ones).

The product of its digits is 442368, while the sum is 46.

The square root of 644418892 is about 25385.4070678412. The cubic root of 644418892 is about 863.7527066472.

The spelling of 644418892 in words is "six hundred forty-four million, four hundred eighteen thousand, eight hundred ninety-two".