643636117 has 4 divisors (see below), whose sum is σ = 671620320. Its totient is φ = 615651916.

The previous prime is 643636079. The next prime is 643636129. The reversal of 643636117 is 711636346.

It is a happy number.

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 643636117 - 2¹⁵ = 643603349 is a prime.

It is a super-2 number, since 2×643636117² = 828534902213675378, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643636157) 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, 13992067 + ... + 13992112.

It is an arithmetic number, because the mean of its divisors is an integer number (167905080).

Almost surely, 2^643636117 is an apocalyptic number.

It is an amenable number.

643636117 is a deficient number, since it is larger than the sum of its proper divisors (27984203).

643636117 is a wasteful number, since it uses less digits than its factorization.

643636117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27984202.

The product of its digits is 54432, while the sum is 37.

The square root of 643636117 is about 25369.9845683832. The cubic root of 643636117 is about 863.4028317544.

The spelling of 643636117 in words is "six hundred forty-three million, six hundred thirty-six thousand, one hundred seventeen".