644949446 has 4 divisors (see below), whose sum is σ = 967424172. Its totient is φ = 322474722.

The previous prime is 644949439. The next prime is 644949457.

644949446 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 644949394 and 644949403.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161237360 + ... + 161237363.

It is an arithmetic number, because the mean of its divisors is an integer number (241856043).

Almost surely, 2^644949446 is an apocalyptic number.

644949446 is a deficient number, since it is larger than the sum of its proper divisors (322474726).

644949446 is a wasteful number, since it uses less digits than its factorization.

644949446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322474725.

The product of its digits is 2985984, while the sum is 50.

The square root of 644949446 is about 25395.8548979947. The cubic root of 644949446 is about 863.9896859123.

The spelling of 644949446 in words is "six hundred forty-four million, nine hundred forty-nine thousand, four hundred forty-six".