641644549 has 16 divisors (see below), whose sum is σ = 836172288. Its totient is φ = 477810432.

The previous prime is 641644477. The next prime is 641644571. The reversal of 641644549 is 945446146.

It is not a de Polignac number, because 641644549 - 2¹¹ = 641642501 is a prime.

It is a super-2 number, since 2×641644549² = 823415454522826802, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641644579) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 205837 + ... + 208930.

It is an arithmetic number, because the mean of its divisors is an integer number (52260768).

Almost surely, 2^641644549 is an apocalyptic number.

It is an amenable number.

641644549 is a deficient number, since it is larger than the sum of its proper divisors (194527739).

641644549 is a wasteful number, since it uses less digits than its factorization.

641644549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414804.

The product of its digits is 414720, while the sum is 43.

The square root of 641644549 is about 25330.7036815008. The cubic root of 641644549 is about 862.5113849649.

The spelling of 641644549 in words is "six hundred forty-one million, six hundred forty-four thousand, five hundred forty-nine".