644080445 has 32 divisors (see below), whose sum is σ = 841560192. Its totient is φ = 471324672.

The previous prime is 644080441. The next prime is 644080471. The reversal of 644080445 is 544080446.

It is a cyclic number.

It is not a de Polignac number, because 644080445 - 2² = 644080441 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644080441) 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 31 ways as a sum of consecutive naturals, for example, 1143734 + ... + 1144296.

It is an arithmetic number, because the mean of its divisors is an integer number (26298756).

Almost surely, 2^644080445 is an apocalyptic number.

It is an amenable number.

644080445 is a deficient number, since it is larger than the sum of its proper divisors (197479747).

644080445 is a wasteful number, since it uses less digits than its factorization.

644080445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 941.

The product of its (nonzero) digits is 61440, while the sum is 35.

The square root of 644080445 is about 25378.7400199458. The cubic root of 644080445 is about 863.6014666651.

Subtracting from 644080445 its reverse (544080446), we obtain a palindrome (99999999).

The spelling of 644080445 in words is "six hundred forty-four million, eighty thousand, four hundred forty-five".