644420346 has 16 divisors (see below), whose sum is σ = 1289711808. Its totient is φ = 214661600.

The previous prime is 644420327. The next prime is 644420347. The reversal of 644420346 is 643024446.

644420346 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (644420347) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26475 + ... + 44606.

It is an arithmetic number, because the mean of its divisors is an integer number (80606988).

Almost surely, 2^644420346 is an apocalyptic number.

644420346 is an abundant number, since it is smaller than the sum of its proper divisors (645291462).

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

644420346 is a wasteful number, since it uses less digits than its factorization.

644420346 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72597.

The product of its (nonzero) digits is 55296, while the sum is 33.

The square root of 644420346 is about 25385.4357063258. The cubic root of 644420346 is about 863.7533562741.

The spelling of 644420346 in words is "six hundred forty-four million, four hundred twenty thousand, three hundred forty-six".