644402442 has 32 divisors (see below), whose sum is σ = 1436443200. Its totient is φ = 191524608.

The previous prime is 644402413. The next prime is 644402483. The reversal of 644402442 is 244204446.

It is an unprimeable number.

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, 164317 + ... + 168192.

It is an arithmetic number, because the mean of its divisors is an integer number (44888850).

Almost surely, 2^644402442 is an apocalyptic number.

644402442 is an abundant number, since it is smaller than the sum of its proper divisors (792040758).

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

644402442 is a wasteful number, since it uses less digits than its factorization.

644402442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332550.

The product of its (nonzero) digits is 24576, while the sum is 30.

The square root of 644402442 is about 25385.0830607268. The cubic root of 644402442 is about 863.7453569491.

Adding to 644402442 its reverse (244204446), we get a palindrome (888606888).

The spelling of 644402442 in words is "six hundred forty-four million, four hundred two thousand, four hundred forty-two".