644692233 has 16 divisors (see below), whose sum is σ = 881922240. Its totient is φ = 418758144.

The previous prime is 644692199. The next prime is 644692261. The reversal of 644692233 is 332296446.

It is not a de Polignac number, because 644692233 - 2¹⁰ = 644691209 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644692191 and 644692200.

It is not an unprimeable number, because it can be changed into a prime (644692333) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3885 + ... + 36117.

It is an arithmetic number, because the mean of its divisors is an integer number (55120140).

Almost surely, 2^644692233 is an apocalyptic number.

It is an amenable number.

644692233 is a deficient number, since it is larger than the sum of its proper divisors (237230007).

644692233 is a wasteful number, since it uses less digits than its factorization.

644692233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32408.

The product of its digits is 186624, while the sum is 39.

The square root of 644692233 is about 25390.7903185387. The cubic root of 644692233 is about 863.8748144137.

The spelling of 644692233 in words is "six hundred forty-four million, six hundred ninety-two thousand, two hundred thirty-three".