644166099 has 6 divisors (see below), whose sum is σ = 930462156. Its totient is φ = 429444060.

The previous prime is 644166097. The next prime is 644166109. The reversal of 644166099 is 990661446.

644166099 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644166099 - 2¹ = 644166097 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644166097) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35786997 + ... + 35787014.

It is an arithmetic number, because the mean of its divisors is an integer number (155077026).

Almost surely, 2^644166099 is an apocalyptic number.

644166099 is a deficient number, since it is larger than the sum of its proper divisors (286296057).

644166099 is a wasteful number, since it uses less digits than its factorization.

644166099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71574017 (or 71574014 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The square root of 644166099 is about 25380.4274786695. The cubic root of 644166099 is about 863.6397474119.

The spelling of 644166099 in words is "six hundred forty-four million, one hundred sixty-six thousand, ninety-nine".