644754222 has 64 divisors (see below), whose sum is σ = 1668418560. Its totient is φ = 180734112.

The previous prime is 644754221. The next prime is 644754251. The reversal of 644754222 is 222457446.

644754222 is a `hidden beast` number, since 644 + 7 + 5 + 4 + 2 + 2 + 2 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644754221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3943 + ... + 36125.

It is an arithmetic number, because the mean of its divisors is an integer number (26069040).

Almost surely, 2^644754222 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644754222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (834209280).

644754222 is an abundant number, since it is smaller than the sum of its proper divisors (1023664338).

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

644754222 is a wasteful number, since it uses less digits than its factorization.

644754222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32254 (or 32248 counting only the distinct ones).

The product of its digits is 107520, while the sum is 36.

The square root of 644754222 is about 25392.0109877103. The cubic root of 644754222 is about 863.9025015367.

The spelling of 644754222 in words is "six hundred forty-four million, seven hundred fifty-four thousand, two hundred twenty-two".