644512245 has 64 divisors (see below), whose sum is σ = 1182988800. Its totient is φ = 296828928.

The previous prime is 644512241. The next prime is 644512259. The reversal of 644512245 is 542215446.

It is not a de Polignac number, because 644512245 - 2² = 644512241 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644512241) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 659197 + ... + 660173.

It is an arithmetic number, because the mean of its divisors is an integer number (18484200).

Almost surely, 2^644512245 is an apocalyptic number.

644512245 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

644512245 is a deficient number, since it is larger than the sum of its proper divisors (538476555).

644512245 is a wasteful number, since it uses less digits than its factorization.

644512245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1214.

The product of its digits is 38400, while the sum is 33.

The square root of 644512245 is about 25387.2457151224. The cubic root of 644512245 is about 863.7944134801.

The spelling of 644512245 in words is "six hundred forty-four million, five hundred twelve thousand, two hundred forty-five".