644068045 has 8 divisors (see below), whose sum is σ = 775756440. Its totient is φ = 513337920.

The previous prime is 644068043. The next prime is 644068049. The reversal of 644068045 is 540860446.

It can be written as a sum of positive squares in 4 ways, for example, as 4888521 + 639179524 = 2211^2 + 25282^2 .

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

It is not a de Polignac number, because 644068045 - 2¹ = 644068043 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644067995 and 644068013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644068043) 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, 238086 + ... + 240775.

It is an arithmetic number, because the mean of its divisors is an integer number (96969555).

Almost surely, 2^644068045 is an apocalyptic number.

It is an amenable number.

644068045 is a deficient number, since it is larger than the sum of its proper divisors (131688395).

644068045 is a wasteful number, since it uses less digits than its factorization.

644068045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 479135.

The product of its (nonzero) digits is 92160, while the sum is 37.

The square root of 644068045 is about 25378.4957198018. The cubic root of 644068045 is about 863.5959245381.

The spelling of 644068045 in words is "six hundred forty-four million, sixty-eight thousand, forty-five".