644026475 has 12 divisors (see below), whose sum is σ = 798913896. Its totient is φ = 515014080.

The previous prime is 644026459. The next prime is 644026499. The reversal of 644026475 is 574620446.

644026475 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644026475 - 2⁴ = 644026459 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 100724 + ... + 106926.

It is an arithmetic number, because the mean of its divisors is an integer number (66576158).

Almost surely, 2^644026475 is an apocalyptic number.

644026475 is a deficient number, since it is larger than the sum of its proper divisors (154887421).

644026475 is a wasteful number, since it uses less digits than its factorization.

644026475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10366 (or 10361 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 38.

The square root of 644026475 is about 25377.6767061132. The cubic root of 644026475 is about 863.5773444853.

The spelling of 644026475 in words is "six hundred forty-four million, twenty-six thousand, four hundred seventy-five".