644375141 has 4 divisors (see below), whose sum is σ = 645473472. Its totient is φ = 643276812.

The previous prime is 644375131. The next prime is 644375201. The reversal of 644375141 is 141573446.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 644375141 - 2¹⁰ = 644374117 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 (644375111) 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 3 ways as a sum of consecutive naturals, for example, 548285 + ... + 549458.

It is an arithmetic number, because the mean of its divisors is an integer number (161368368).

Almost surely, 2^644375141 is an apocalyptic number.

It is an amenable number.

644375141 is a deficient number, since it is larger than the sum of its proper divisors (1098331).

644375141 is a wasteful number, since it uses less digits than its factorization.

644375141 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1098330.

The product of its digits is 40320, while the sum is 35.

The square root of 644375141 is about 25384.5453179686. The cubic root of 644375141 is about 863.7331588549.

The spelling of 644375141 in words is "six hundred forty-four million, three hundred seventy-five thousand, one hundred forty-one".