644802246 has 48 divisors (see below), whose sum is σ = 1533504960. Its totient is φ = 194186160.

The previous prime is 644802229. The next prime is 644802251. The reversal of 644802246 is 642208446.

It is a happy number.

644802246 is a `hidden beast` number, since 644 + 8 + 0 + 2 + 2 + 4 + 6 = 666.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 644802246.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22285 + ... + 42263.

It is an arithmetic number, because the mean of its divisors is an integer number (31948020).

Almost surely, 2^644802246 is an apocalyptic number.

644802246 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 644802246, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (766752480).

644802246 is an abundant number, since it is smaller than the sum of its proper divisors (888702714).

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

644802246 is a wasteful number, since it uses less digits than its factorization.

644802246 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20161 (or 20158 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 36.

The square root of 644802246 is about 25392.9566218666. The cubic root of 644802246 is about 863.9239500320.

The spelling of 644802246 in words is "six hundred forty-four million, eight hundred two thousand, two hundred forty-six".