644161305 has 32 divisors (see below), whose sum is σ = 1063384704. Its totient is φ = 332729856.

The previous prime is 644161289. The next prime is 644161321. The reversal of 644161305 is 503161446.

644161305 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (644161289) and next prime (644161321).

It is not a de Polignac number, because 644161305 - 2⁴ = 644161289 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 123429 + ... + 128541.

It is an arithmetic number, because the mean of its divisors is an integer number (33230772).

Almost surely, 2^644161305 is an apocalyptic number.

It is an amenable number.

644161305 is a deficient number, since it is larger than the sum of its proper divisors (419223399).

644161305 is a wasteful number, since it uses less digits than its factorization.

644161305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5385.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 644161305 is about 25380.3330356400. Note that the first 3 decimals coincide. The cubic root of 644161305 is about 863.6376049525.

The spelling of 644161305 in words is "six hundred forty-four million, one hundred sixty-one thousand, three hundred five".