641644139 has 4 divisors (see below), whose sum is σ = 641700840. Its totient is φ = 641587440.

The previous prime is 641644127. The next prime is 641644153. The reversal of 641644139 is 931446146.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 641644139 - 2⁴ = 641644123 is a prime.

It is a super-2 number, since 2×641644139² = 823414402226102642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (641644189) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4922 + ... + 36159.

It is an arithmetic number, because the mean of its divisors is an integer number (160425210).

Almost surely, 2^641644139 is an apocalyptic number.

641644139 is a deficient number, since it is larger than the sum of its proper divisors (56701).

641644139 is a wasteful number, since it uses less digits than its factorization.

641644139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56700.

The product of its digits is 62208, while the sum is 38.

The square root of 641644139 is about 25330.6955885542. The cubic root of 641644139 is about 862.5112012548.

The spelling of 641644139 in words is "six hundred forty-one million, six hundred forty-four thousand, one hundred thirty-nine".