644031442 has 8 divisors (see below), whose sum is σ = 966586032. Its totient is φ = 321836100.

The previous prime is 644031413. The next prime is 644031481. The reversal of 644031442 is 244130446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 644031442.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85284 + ... + 92527.

It is an arithmetic number, because the mean of its divisors is an integer number (120823254).

Almost surely, 2^644031442 is an apocalyptic number.

644031442 is a deficient number, since it is larger than the sum of its proper divisors (322554590).

644031442 is a wasteful number, since it uses less digits than its factorization.

644031442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179624.

The product of its (nonzero) digits is 9216, while the sum is 28.

The square root of 644031442 is about 25377.7745675227. The cubic root of 644031442 is about 863.5795645688.

Adding to 644031442 its reverse (244130446), we get a palindrome (888161888).

The spelling of 644031442 in words is "six hundred forty-four million, thirty-one thousand, four hundred forty-two".