643466920 has 32 divisors (see below), whose sum is σ = 1524002400. Its totient is φ = 243839808.

The previous prime is 643466917. The next prime is 643466927. The reversal of 643466920 is 29664346.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (643466927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 422574 + ... + 424093.

It is an arithmetic number, because the mean of its divisors is an integer number (47625075).

Almost surely, 2^643466920 is an apocalyptic number.

It is an amenable number.

643466920 is an abundant number, since it is smaller than the sum of its proper divisors (880535480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643466920 is a wasteful number, since it uses less digits than its factorization.

643466920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 846697 (or 846693 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 40.

The square root of 643466920 is about 25366.6497590833. The cubic root of 643466920 is about 863.3271689341.

The spelling of 643466920 in words is "six hundred forty-three million, four hundred sixty-six thousand, nine hundred twenty".