643764879 has 24 divisors (see below), whose sum is σ = 962916864. Its totient is φ = 414018000.

The previous prime is 643764851. The next prime is 643764883. The reversal of 643764879 is 978467346.

It is a happy number.

It is not a de Polignac number, because 643764879 - 2¹¹ = 643762831 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643764829) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 88864 + ... + 95834.

It is an arithmetic number, because the mean of its divisors is an integer number (40121536).

Almost surely, 2^643764879 is an apocalyptic number.

643764879 is a deficient number, since it is larger than the sum of its proper divisors (319151985).

643764879 is a wasteful number, since it uses less digits than its factorization.

643764879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7339 (or 7336 counting only the distinct ones).

The product of its digits is 6096384, while the sum is 54.

The square root of 643764879 is about 25372.5221253229. The cubic root of 643764879 is about 863.4604036545.

The spelling of 643764879 in words is "six hundred forty-three million, seven hundred sixty-four thousand, eight hundred seventy-nine".