644474496 has 32 divisors (see below), whose sum is σ = 1711886400. Its totient is φ = 214824704.

The previous prime is 644474491. The next prime is 644474521. The reversal of 644474496 is 694474446.

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

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (644474491) 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, 838776 + ... + 839543.

It is an arithmetic number, because the mean of its divisors is an integer number (53496450).

Almost surely, 2^644474496 is an apocalyptic number.

It is an amenable number.

644474496 is an abundant number, since it is smaller than the sum of its proper divisors (1067411904).

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

644474496 is a wasteful number, since it uses less digits than its factorization.

644474496 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1678336 (or 1678324 counting only the distinct ones).

The product of its digits is 2322432, while the sum is 48.

The square root of 644474496 is about 25386.5022403639. The cubic root of 644474496 is about 863.7775490413. Note that the first 3 decimals are identical.

The spelling of 644474496 in words is "six hundred forty-four million, four hundred seventy-four thousand, four hundred ninety-six".