644079194 has 16 divisors (see below), whose sum is σ = 1054442880. Its totient is φ = 292625760.

The previous prime is 644079181. The next prime is 644079197. The reversal of 644079194 is 491970446.

It is not an unprimeable number, because it can be changed into a prime (644079197) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 52367 + ... + 63485.

It is an arithmetic number, because the mean of its divisors is an integer number (65902680).

Almost surely, 2^644079194 is an apocalyptic number.

644079194 is a deficient number, since it is larger than the sum of its proper divisors (410363686).

644079194 is a wasteful number, since it uses less digits than its factorization.

644079194 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13765.

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 644079194 is about 25378.7153733202. The cubic root of 644079194 is about 863.6009075393.

The spelling of 644079194 in words is "six hundred forty-four million, seventy-nine thousand, one hundred ninety-four".