643864629 has 16 divisors (see below), whose sum is σ = 864820224. Its totient is φ = 426086400.

The previous prime is 643864619. The next prime is 643864633. The reversal of 643864629 is 926468346.

It is not a de Polignac number, because 643864629 - 2⁸ = 643864373 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643864619) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 366417 + ... + 368169.

It is an arithmetic number, because the mean of its divisors is an integer number (54051264).

Almost surely, 2^643864629 is an apocalyptic number.

It is an amenable number.

643864629 is a deficient number, since it is larger than the sum of its proper divisors (220955595).

643864629 is a wasteful number, since it uses less digits than its factorization.

643864629 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2588.

The product of its digits is 1492992, while the sum is 48.

The square root of 643864629 is about 25374.4877583765. The cubic root of 643864629 is about 863.5049984695.

The spelling of 643864629 in words is "six hundred forty-three million, eight hundred sixty-four thousand, six hundred twenty-nine".