644444042 has 16 divisors (see below), whose sum is σ = 1055116800. Its totient is φ = 292770240.

The previous prime is 644444039. The next prime is 644444051. The reversal of 644444042 is 240444446.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39959 + ... + 53717.

It is an arithmetic number, because the mean of its divisors is an integer number (65944800).

Almost surely, 2^644444042 is an apocalyptic number.

644444042 is a deficient number, since it is larger than the sum of its proper divisors (410672758).

644444042 is a wasteful number, since it uses less digits than its factorization.

644444042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15901.

The product of its (nonzero) digits is 49152, while the sum is 32.

The square root of 644444042 is about 25385.9024263468. The cubic root of 644444042 is about 863.7639431779.

Adding to 644444042 its reverse (240444446), we get a palindrome (884888488).

It can be divided in two parts, 64444 and 4042, that added together give a palindrome (68486).

The spelling of 644444042 in words is "six hundred forty-four million, four hundred forty-four thousand, forty-two".