644355246 has 32 divisors (see below), whose sum is σ = 1375660800. Its totient is φ = 200612160.

The previous prime is 644355241. The next prime is 644355247. The reversal of 644355246 is 642553446.

It is a super-3 number, since 3×644355246³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644355241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31711 + ... + 47898.

It is an arithmetic number, because the mean of its divisors is an integer number (42989400).

Almost surely, 2^644355246 is an apocalyptic number.

644355246 is an abundant number, since it is smaller than the sum of its proper divisors (731305554).

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

644355246 is a wasteful number, since it uses less digits than its factorization.

644355246 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79704.

The product of its digits is 345600, while the sum is 39.

The square root of 644355246 is about 25384.1534426500. The cubic root of 644355246 is about 863.7242695465.

The spelling of 644355246 in words is "six hundred forty-four million, three hundred fifty-five thousand, two hundred forty-six".