643669989 has 8 divisors (see below), whose sum is σ = 859009152. Its totient is φ = 428722080.

The previous prime is 643669951. The next prime is 643670003. The reversal of 643669989 is 989966346.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 643669989 - 2²⁸ = 375234533 is a prime.

It is a super-2 number, since 2×643669989² = 828622109478520242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643669919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 93952 + ... + 100569.

It is an arithmetic number, because the mean of its divisors is an integer number (107376144).

Almost surely, 2^643669989 is an apocalyptic number.

It is an amenable number.

643669989 is a deficient number, since it is larger than the sum of its proper divisors (215339163).

643669989 is a wasteful number, since it uses less digits than its factorization.

643669989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195627.

The product of its digits is 15116544, while the sum is 60.

The square root of 643669989 is about 25370.6521201171. The cubic root of 643669989 is about 863.4179773038.

The spelling of 643669989 in words is "six hundred forty-three million, six hundred sixty-nine thousand, nine hundred eighty-nine".