644911233 has 4 divisors (see below), whose sum is σ = 859881648. Its totient is φ = 429940820.

The previous prime is 644911231. The next prime is 644911271. The reversal of 644911233 is 332119446.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 644911233 - 2¹ = 644911231 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644911194 and 644911203.

It is not an unprimeable number, because it can be changed into a prime (644911231) 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, 107485203 + ... + 107485208.

It is an arithmetic number, because the mean of its divisors is an integer number (214970412).

Almost surely, 2^644911233 is an apocalyptic number.

It is an amenable number.

644911233 is a deficient number, since it is larger than the sum of its proper divisors (214970415).

644911233 is a wasteful number, since it uses less digits than its factorization.

644911233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214970414.

The product of its digits is 15552, while the sum is 33.

The square root of 644911233 is about 25395.1025396630. The cubic root of 644911233 is about 863.9726218927.

The spelling of 644911233 in words is "six hundred forty-four million, nine hundred eleven thousand, two hundred thirty-three".