643666613 has 8 divisors (see below), whose sum is σ = 660264000. Its totient is φ = 627143328.

The previous prime is 643666579. The next prime is 643666619. The reversal of 643666613 is 316666346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643666613 - 2⁶ = 643666549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643666619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 713 + ... + 35886.

It is an arithmetic number, because the mean of its divisors is an integer number (82533000).

Almost surely, 2^643666613 is an apocalyptic number.

It is an amenable number.

643666613 is a deficient number, since it is larger than the sum of its proper divisors (16597387).

643666613 is a wasteful number, since it uses less digits than its factorization.

643666613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37051.

The product of its digits is 279936, while the sum is 41.

The square root of 643666613 is about 25370.5855864621. The cubic root of 643666613 is about 863.4164677807.

The spelling of 643666613 in words is "six hundred forty-three million, six hundred sixty-six thousand, six hundred thirteen".