644000125 has 8 divisors (see below), whose sum is σ = 803712312. Its totient is φ = 515200000.

The previous prime is 644000111. The next prime is 644000131. The reversal of 644000125 is 521000446.

644000125 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 78464164 + 565535961 = 8858^2 + 23781^2 .

It is not a de Polignac number, because 644000125 - 2⁹ = 643999613 is a prime.

It is a super-2 number, since 2×644000125² = 829472322000031250, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644000096 and 644000105.

It is a congruent number.

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, 2575876 + ... + 2576125.

It is an arithmetic number, because the mean of its divisors is an integer number (100464039).

Almost surely, 2^644000125 is an apocalyptic number.

It is an amenable number.

644000125 is a deficient number, since it is larger than the sum of its proper divisors (159712187).

644000125 is an equidigital number, since it uses as much as digits as its factorization.

644000125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5152016 (or 5152006 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 644000125 is about 25377.1575437439. The cubic root of 644000125 is about 863.5655667224.

The spelling of 644000125 in words is "six hundred forty-four million, one hundred twenty-five", and thus it is an aban number.