643523899 has 16 divisors (see below), whose sum is σ = 690838848. Its totient is φ = 597307392.

The previous prime is 643523897. The next prime is 643523921. The reversal of 643523899 is 998325346.

It is a cyclic number.

It is not a de Polignac number, because 643523899 - 2¹ = 643523897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643523897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 654162 + ... + 655144.

It is an arithmetic number, because the mean of its divisors is an integer number (43177428).

Almost surely, 2^643523899 is an apocalyptic number.

643523899 is a deficient number, since it is larger than the sum of its proper divisors (47314949).

643523899 is a wasteful number, since it uses less digits than its factorization.

643523899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1494.

The product of its digits is 1399680, while the sum is 49.

The square root of 643523899 is about 25367.7728427231. The cubic root of 643523899 is about 863.3526507242.

The spelling of 643523899 in words is "six hundred forty-three million, five hundred twenty-three thousand, eight hundred ninety-nine".