644611 has 4 divisors (see below), whose sum is σ = 703224. Its totient is φ = 586000.

The previous prime is 644599. The next prime is 644617. The reversal of 644611 is 116446.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 644611 - 2¹¹ = 642563 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644617) 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, 29290 + ... + 29311.

It is an arithmetic number, because the mean of its divisors is an integer number (175806).

2⁶⁴⁴⁶¹¹ is an apocalyptic number.

644611 is a deficient number, since it is larger than the sum of its proper divisors (58613).

644611 is a wasteful number, since it uses less digits than its factorization.

644611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58612.

The product of its digits is 576, while the sum is 22.

The square root of 644611 is about 802.8767028629. The cubic root of 644611 is about 86.3838529353.

The spelling of 644611 in words is "six hundred forty-four thousand, six hundred eleven".