643626713 has 4 divisors (see below), whose sum is σ = 646437540. Its totient is φ = 640815888.

The previous prime is 643626689. The next prime is 643626773. The reversal of 643626713 is 317626346.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 317626346 = 2 ⋅158813173.

It can be written as a sum of positive squares in 2 ways, for example, as 534904384 + 108722329 = 23128^2 + 10427^2 .

It is a cyclic number.

It is not a de Polignac number, because 643626713 - 2⁶ = 643626649 is a prime.

It is a super-3 number, since 3×643626713³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643626773) 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, 1405070 + ... + 1405527.

It is an arithmetic number, because the mean of its divisors is an integer number (161609385).

Almost surely, 2^643626713 is an apocalyptic number.

It is an amenable number.

643626713 is a deficient number, since it is larger than the sum of its proper divisors (2810827).

643626713 is a wasteful number, since it uses less digits than its factorization.

643626713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2810826.

The product of its digits is 108864, while the sum is 38.

The square root of 643626713 is about 25369.7992305812. The cubic root of 643626713 is about 863.3986267492.

The spelling of 643626713 in words is "six hundred forty-three million, six hundred twenty-six thousand, seven hundred thirteen".