644947124 has 12 divisors (see below), whose sum is σ = 1167576900. Its totient is φ = 311353728.

The previous prime is 644947109. The next prime is 644947129. The reversal of 644947124 is 421749446.

It can be written as a sum of positive squares in 2 ways, for example, as 237714724 + 407232400 = 15418^2 + 20180^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644947129) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2779829 + ... + 2780060.

It is an arithmetic number, because the mean of its divisors is an integer number (97298075).

Almost surely, 2^644947124 is an apocalyptic number.

It is an amenable number.

644947124 is a deficient number, since it is larger than the sum of its proper divisors (522629776).

644947124 is a wasteful number, since it uses less digits than its factorization.

644947124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5559922 (or 5559920 counting only the distinct ones).

The product of its digits is 193536, while the sum is 41.

The square root of 644947124 is about 25395.8091818316. The cubic root of 644947124 is about 863.9886490421.

The spelling of 644947124 in words is "six hundred forty-four million, nine hundred forty-seven thousand, one hundred twenty-four".