643864234 has 48 divisors (see below), whose sum is σ = 1092530376. Its totient is φ = 282839040.

The previous prime is 643864217. The next prime is 643864237. The reversal of 643864234 is 432468346.

It can be written as a sum of positive squares in 4 ways, for example, as 437855625 + 206008609 = 20925^2 + 14353^2 .

It is a super-2 number, since 2×643864234² = 829122303648813512, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (643864237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1823802 + ... + 1824154.

Almost surely, 2^643864234 is an apocalyptic number.

643864234 is a deficient number, since it is larger than the sum of its proper divisors (448666142).

643864234 is a wasteful number, since it uses less digits than its factorization.

643864234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503 (or 472 counting only the distinct ones).

The product of its digits is 331776, while the sum is 40.

The square root of 643864234 is about 25374.4799749670. The cubic root of 643864234 is about 863.5048218876.

The spelling of 643864234 in words is "six hundred forty-three million, eight hundred sixty-four thousand, two hundred thirty-four".