643853233 has 6 divisors (see below), whose sum is σ = 659176674. Its totient is φ = 628878096.

The previous prime is 643853227. The next prime is 643853251. The reversal of 643853233 is 332358346.

It can be written as a sum of positive squares in only one way, i.e., 641456929 + 2396304 = 25327^2 + 1548^2 .

It is not a de Polignac number, because 643853233 - 2⁵ = 643853201 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 643853192 and 643853201.

It is not an unprimeable number, because it can be changed into a prime (643853263) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 172260 + ... + 175957.

It is an arithmetic number, because the mean of its divisors is an integer number (109862779).

Almost surely, 2^643853233 is an apocalyptic number.

It is an amenable number.

643853233 is a deficient number, since it is larger than the sum of its proper divisors (15323441).

643853233 is an equidigital number, since it uses as much as digits as its factorization.

643853233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 348303 (or 348260 counting only the distinct ones).

The product of its digits is 155520, while the sum is 37.

The square root of 643853233 is about 25374.2632011257. The cubic root of 643853233 is about 863.4999039406.

The spelling of 643853233 in words is "six hundred forty-three million, eight hundred fifty-three thousand, two hundred thirty-three".