644080447 has 8 divisors (see below), whose sum is σ = 654260912. Its totient is φ = 633916800.

The previous prime is 644080441. The next prime is 644080471. The reversal of 644080447 is 744080446.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644080447 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 polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 89047 + ... + 96007.

It is an arithmetic number, because the mean of its divisors is an integer number (81782614).

Almost surely, 2^644080447 is an apocalyptic number.

644080447 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

644080447 is a deficient number, since it is larger than the sum of its proper divisors (10180465).

644080447 is a wasteful number, since it uses less digits than its factorization.

644080447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8409.

The product of its (nonzero) digits is 86016, while the sum is 37.

The square root of 644080447 is about 25378.7400593489. The cubic root of 644080447 is about 863.6014675590.

Subtracting 644080447 from its reverse (744080446), we obtain a palindrome (99999999).

The spelling of 644080447 in words is "six hundred forty-four million, eighty thousand, four hundred forty-seven".