643466979 has 24 divisors (see below), whose sum is σ = 947810864. Its totient is φ = 420552000.

The previous prime is 643466959. The next prime is 643467043. The reversal of 643466979 is 979664346.

643466979 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 643466979 - 2²³ = 635078371 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643466959) 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, 179949 + ... + 183489.

Almost surely, 2^643466979 is an apocalyptic number.

643466979 is a deficient number, since it is larger than the sum of its proper divisors (304343885).

643466979 is a wasteful number, since it uses less digits than its factorization.

643466979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3939 (or 3936 counting only the distinct ones).

The product of its digits is 5878656, while the sum is 54.

The square root of 643466979 is about 25366.6509220275. The cubic root of 643466979 is about 863.3271953205.

The spelling of 643466979 in words is "six hundred forty-three million, four hundred sixty-six thousand, nine hundred seventy-nine".