644822142 has 16 divisors (see below), whose sum is σ = 1307809152. Its totient is φ = 211913240.

The previous prime is 644822131. The next prime is 644822159. The reversal of 644822142 is 241228446.

It is a congruent number.

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, 756408 + ... + 757259.

It is an arithmetic number, because the mean of its divisors is an integer number (81738072).

Almost surely, 2^644822142 is an apocalyptic number.

644822142 is an abundant number, since it is smaller than the sum of its proper divisors (662987010).

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

644822142 is a wasteful number, since it uses less digits than its factorization.

644822142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1513743.

The product of its digits is 24576, while the sum is 33.

The square root of 644822142 is about 25393.3483810229. The cubic root of 644822142 is about 863.9328356784.

The spelling of 644822142 in words is "six hundred forty-four million, eight hundred twenty-two thousand, one hundred forty-two".