644499 has 12 divisors (see below), whose sum is σ = 980200. Its totient is φ = 406944.

The previous prime is 644491. The next prime is 644507. The reversal of 644499 is 994446.

644499 is a `hidden beast` number, since 644 + 4 + 9 + 9 = 666.

It is an interprime number because it is at equal distance from previous prime (644491) and next prime (644507).

It is not a de Polignac number, because 644499 - 2³ = 644491 is a prime.

It is a super-2 number, since 2×644499² = 830757922002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1714 + ... + 2055.

2⁶⁴⁴⁴⁹⁹ is an apocalyptic number.

644499 is a deficient number, since it is larger than the sum of its proper divisors (335701).

644499 is a wasteful number, since it uses less digits than its factorization.

644499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3794 (or 3791 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 644499 is about 802.8069506426. The cubic root of 644499 is about 86.3788496326.

The spelling of 644499 in words is "six hundred forty-four thousand, four hundred ninety-nine".