643676643 has 12 divisors (see below), whose sum is σ = 970179600. Its totient is φ = 410460336.

The previous prime is 643676641. The next prime is 643676647. The reversal of 643676643 is 346676346.

It is not a de Polignac number, because 643676643 - 2¹ = 643676641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643676641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1554568 + ... + 1554981.

It is an arithmetic number, because the mean of its divisors is an integer number (80848300).

Almost surely, 2^643676643 is an apocalyptic number.

643676643 is a deficient number, since it is larger than the sum of its proper divisors (326502957).

643676643 is a wasteful number, since it uses less digits than its factorization.

643676643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3109578 (or 3109575 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 45.

The square root of 643676643 is about 25370.7832555481. The cubic root of 643676643 is about 863.4209525155.

The spelling of 643676643 in words is "six hundred forty-three million, six hundred seventy-six thousand, six hundred forty-three".