644422142 has 32 divisors (see below), whose sum is σ = 1241436672. Its totient is φ = 243850464.

The previous prime is 644422139. The next prime is 644422151. The reversal of 644422142 is 241224446.

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 15 ways as a sum of consecutive naturals, for example, 72788 + ... + 81159.

It is an arithmetic number, because the mean of its divisors is an integer number (38794896).

Almost surely, 2^644422142 is an apocalyptic number.

644422142 is a deficient number, since it is larger than the sum of its proper divisors (597014530).

644422142 is a wasteful number, since it uses less digits than its factorization.

644422142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153992.

The product of its digits is 12288, while the sum is 29.

The square root of 644422142 is about 25385.4710809156. The cubic root of 644422142 is about 863.7541587004.

Adding to 644422142 its reverse (241224446), we get a palindrome (885646588).

The spelling of 644422142 in words is "six hundred forty-four million, four hundred twenty-two thousand, one hundred forty-two".