644469 has 8 divisors (see below), whose sum is σ = 982080. Its totient is φ = 368256.

The previous prime is 644447. The next prime is 644489. The reversal of 644469 is 964446.

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

It is not a de Polignac number, because 644469 - 2⁷ = 644341 is a prime.

It is a super-2 number, since 2×644469² = 830680583922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644489) 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, 15324 + ... + 15365.

It is an arithmetic number, because the mean of its divisors is an integer number (122760).

2⁶⁴⁴⁴⁶⁹ is an apocalyptic number.

It is an amenable number.

644469 is a deficient number, since it is larger than the sum of its proper divisors (337611).

644469 is a wasteful number, since it uses less digits than its factorization.

644469 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30699.

The product of its digits is 20736, while the sum is 33.

The square root of 644469 is about 802.7882659830. The cubic root of 644469 is about 86.3775093638.

The spelling of 644469 in words is "six hundred forty-four thousand, four hundred sixty-nine".