644833238 has 24 divisors (see below), whose sum is σ = 1128885912. Its totient is φ = 275444064.

The previous prime is 644833237. The next prime is 644833271. The reversal of 644833238 is 832338446.

It is a junction number, because it is equal to n+sod(n) for n = 644833195 and 644833204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644833237) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19370 + ... + 40802.

It is an arithmetic number, because the mean of its divisors is an integer number (47036913).

Almost surely, 2^644833238 is an apocalyptic number.

644833238 is a deficient number, since it is larger than the sum of its proper divisors (484052674).

644833238 is a wasteful number, since it uses less digits than its factorization.

644833238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21756 (or 21749 counting only the distinct ones).

The product of its digits is 331776, while the sum is 41.

The square root of 644833238 is about 25393.5668624949. The cubic root of 644833238 is about 863.9377911243.

The spelling of 644833238 in words is "six hundred forty-four million, eight hundred thirty-three thousand, two hundred thirty-eight".