643577393 has 4 divisors (see below), whose sum is σ = 643628148. Its totient is φ = 643526640.

The previous prime is 643577377. The next prime is 643577399. The reversal of 643577393 is 393775346.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 354305329 + 289272064 = 18823^2 + 17008^2 .

It is a cyclic number.

It is not a de Polignac number, because 643577393 - 2⁴ = 643577377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643577399) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11723 + ... + 37743.

It is an arithmetic number, because the mean of its divisors is an integer number (160907037).

Almost surely, 2^643577393 is an apocalyptic number.

It is an amenable number.

643577393 is a deficient number, since it is larger than the sum of its proper divisors (50755).

643577393 is a wasteful number, since it uses less digits than its factorization.

643577393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50754.

The product of its digits is 1428840, while the sum is 47.

The square root of 643577393 is about 25368.8271900772. The cubic root of 643577393 is about 863.3765726055.

The spelling of 643577393 in words is "six hundred forty-three million, five hundred seventy-seven thousand, three hundred ninety-three".