644495026 has 32 divisors (see below), whose sum is σ = 1121807232. Its totient is φ = 272004480.

The previous prime is 644495017. The next prime is 644495099. The reversal of 644495026 is 620594446.

It is a happy number.

644495026 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 644495026.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 269950 + ... + 272326.

It is an arithmetic number, because the mean of its divisors is an integer number (35056476).

Almost surely, 2^644495026 is an apocalyptic number.

644495026 is a deficient number, since it is larger than the sum of its proper divisors (477312206).

644495026 is a wasteful number, since it uses less digits than its factorization.

644495026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2674.

The product of its (nonzero) digits is 207360, while the sum is 40.

The square root of 644495026 is about 25386.9065858761. The cubic root of 644495026 is about 863.7867209402.

The spelling of 644495026 in words is "six hundred forty-four million, four hundred ninety-five thousand, twenty-six".