644330406 has 8 divisors (see below), whose sum is σ = 1288660824. Its totient is φ = 214776800.

The previous prime is 644330387. The next prime is 644330419. The reversal of 644330406 is 604033446.

It is a sphenic number, since it is the product of 3 distinct primes.

644330406 is an admirable number.

It is a super-2 number, since 2×644330406² = 830323344192249672, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53694195 + ... + 53694206.

It is an arithmetic number, because the mean of its divisors is an integer number (161082603).

Almost surely, 2^644330406 is an apocalyptic number.

644330406 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644330406 is a wasteful number, since it uses less digits than its factorization.

644330406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107388406.

The product of its (nonzero) digits is 20736, while the sum is 30.

The square root of 644330406 is about 25383.6641563034. The cubic root of 644330406 is about 863.7131705000.

The spelling of 644330406 in words is "six hundred forty-four million, three hundred thirty thousand, four hundred six".