644461 has 8 divisors (see below), whose sum is σ = 686880. Its totient is φ = 602928.

The previous prime is 644447. The next prime is 644489. The reversal of 644461 is 164446.

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

It is a cyclic number.

It is not a de Polignac number, because 644461 - 2⁹ = 643949 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 (644401) 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, 1875 + ... + 2191.

It is an arithmetic number, because the mean of its divisors is an integer number (85860).

2⁶⁴⁴⁴⁶¹ is an apocalyptic number.

It is an amenable number.

644461 is a deficient number, since it is larger than the sum of its proper divisors (42419).

644461 is a wasteful number, since it uses less digits than its factorization.

644461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 443.

The product of its digits is 2304, while the sum is 25.

The square root of 644461 is about 802.7832833337. The cubic root of 644461 is about 86.3771519517.

The spelling of 644461 in words is "six hundred forty-four thousand, four hundred sixty-one".