644042829 has 32 divisors (see below), whose sum is σ = 919659520. Its totient is φ = 399748608.

The previous prime is 644042821. The next prime is 644042837. The reversal of 644042829 is 928240446.

It is an interprime number because it is at equal distance from previous prime (644042821) and next prime (644042837).

It is not a de Polignac number, because 644042829 - 2³ = 644042821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644042821) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 956637 + ... + 957309.

It is an arithmetic number, because the mean of its divisors is an integer number (28739360).

Almost surely, 2^644042829 is an apocalyptic number.

It is an amenable number.

644042829 is a deficient number, since it is larger than the sum of its proper divisors (275616691).

644042829 is a wasteful number, since it uses less digits than its factorization.

644042829 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 961.

The product of its (nonzero) digits is 110592, while the sum is 39.

The square root of 644042829 is about 25377.9989163842. The cubic root of 644042829 is about 863.5846541353.

The spelling of 644042829 in words is "six hundred forty-four million, forty-two thousand, eight hundred twenty-nine".