644120322 has 16 divisors (see below), whose sum is σ = 1288870752. Its totient is φ = 214601760.

The previous prime is 644120299. The next prime is 644120339. The reversal of 644120322 is 223021446.

It is a junction number, because it is equal to n+sod(n) for n = 644120292 and 644120301.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12403 + ... + 37974.

It is an arithmetic number, because the mean of its divisors is an integer number (80554422).

Almost surely, 2^644120322 is an apocalyptic number.

644120322 is an abundant number, since it is smaller than the sum of its proper divisors (644750430).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644120322 is a wasteful number, since it uses less digits than its factorization.

644120322 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52513.

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 644120322 is about 25379.5256456853. The cubic root of 644120322 is about 863.6192890377.

Adding to 644120322 its reverse (223021446), we get a palindrome (867141768).

The spelling of 644120322 in words is "six hundred forty-four million, one hundred twenty thousand, three hundred twenty-two".