643676507 has 4 divisors (see below), whose sum is σ = 659375976. Its totient is φ = 627977040.

The previous prime is 643676477. The next prime is 643676521. The reversal of 643676507 is 705676346.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 705676346 = 2 ⋅352838173.

It is a cyclic number.

It is not a de Polignac number, because 643676507 - 2⁸ = 643676251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643676587) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7849673 + ... + 7849754.

It is an arithmetic number, because the mean of its divisors is an integer number (164843994).

Almost surely, 2^643676507 is an apocalyptic number.

643676507 is a deficient number, since it is larger than the sum of its proper divisors (15699469).

643676507 is a wasteful number, since it uses less digits than its factorization.

643676507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15699468.

The product of its (nonzero) digits is 635040, while the sum is 44.

The square root of 643676507 is about 25370.7805752996. The cubic root of 643676507 is about 863.4208917058.

The spelling of 643676507 in words is "six hundred forty-three million, six hundred seventy-six thousand, five hundred seven".