644334461 has 4 divisors (see below), whose sum is σ = 644438592. Its totient is φ = 644230332.

The previous prime is 644334407. The next prime is 644334463. The reversal of 644334461 is 164433446.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644334461 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 (644334463) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42155 + ... + 55368.

It is an arithmetic number, because the mean of its divisors is an integer number (161109648).

Almost surely, 2^644334461 is an apocalyptic number.

It is an amenable number.

644334461 is a deficient number, since it is larger than the sum of its proper divisors (104131).

644334461 is an equidigital number, since it uses as much as digits as its factorization.

644334461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104130.

The product of its digits is 82944, while the sum is 35.

The square root of 644334461 is about 25383.7440303829. The cubic root of 644334461 is about 863.7149823808.

It can be divided in two parts, 6443 and 34461, that added together give a palindrome (40904).

The spelling of 644334461 in words is "six hundred forty-four million, three hundred thirty-four thousand, four hundred sixty-one".