643979932 has 24 divisors (see below), whose sum is σ = 1134717696. Its totient is φ = 319782768.

The previous prime is 643979929. The next prime is 643979933. The reversal of 643979932 is 239979346.

It is a self number, because there is not a number n which added to its sum of digits gives 643979932.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643979933) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 583293 + ... + 584395.

It is an arithmetic number, because the mean of its divisors is an integer number (47279904).

Almost surely, 2^643979932 is an apocalyptic number.

It is an amenable number.

643979932 is a deficient number, since it is larger than the sum of its proper divisors (490737764).

643979932 is a wasteful number, since it uses less digits than its factorization.

643979932 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1977 (or 1975 counting only the distinct ones).

The product of its digits is 2204496, while the sum is 52.

The square root of 643979932 is about 25376.7596828279. The cubic root of 643979932 is about 863.5565407605.

The spelling of 643979932 in words is "six hundred forty-three million, nine hundred seventy-nine thousand, nine hundred thirty-two".