644342250 has 128 divisors (see below), whose sum is σ = 1713254400. Its totient is φ = 160833600.

The previous prime is 644342243. The next prime is 644342261. The reversal of 644342250 is 52243446.

It is a Harshad number since it is a multiple of its sum of digits (30).

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 63 ways as a sum of consecutive naturals, for example, 1467531 + ... + 1467969.

It is an arithmetic number, because the mean of its divisors is an integer number (13384800).

Almost surely, 2^644342250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644342250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (856627200).

644342250 is an abundant number, since it is smaller than the sum of its proper divisors (1068912150).

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

644342250 is a wasteful number, since it uses less digits than its factorization.

644342250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 581 (or 571 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 30.

The square root of 644342250 is about 25383.8974548827. The cubic root of 644342250 is about 863.7184626897.

Adding to 644342250 its reverse (52243446), we get a palindrome (696585696).

The spelling of 644342250 in words is "six hundred forty-four million, three hundred forty-two thousand, two hundred fifty".