643849794 has 24 divisors (see below), whose sum is σ = 1594295040. Its totient is φ = 183957048.

The previous prime is 643849769. The next prime is 643849799. The reversal of 643849794 is 497948346.

It is a happy number.

643849794 is a `hidden beast` number, since 64 + 3 + 8 + 497 + 94 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 643849794.

It is not an unprimeable number, because it can be changed into a prime (643849799) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2554834 + ... + 2555085.

It is an arithmetic number, because the mean of its divisors is an integer number (66428960).

Almost surely, 2^643849794 is an apocalyptic number.

643849794 is an abundant number, since it is smaller than the sum of its proper divisors (950445246).

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

643849794 is a wasteful number, since it uses less digits than its factorization.

643849794 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5109934 (or 5109931 counting only the distinct ones).

The product of its digits is 5225472, while the sum is 54.

The square root of 643849794 is about 25374.1954355207. The cubic root of 643849794 is about 863.4983665398.

The spelling of 643849794 in words is "six hundred forty-three million, eight hundred forty-nine thousand, seven hundred ninety-four".