66643563215 has 4 divisors (see below), whose sum is σ = 79972275864. Its totient is φ = 53314850568.

The previous prime is 66643563199. The next prime is 66643563223. The reversal of 66643563215 is 51236534666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66643563215 - 2⁴ = 66643563199 is a prime.

It is a super-2 number, since 2×66643563215² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66643563215.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6664356317 + ... + 6664356326.

It is an arithmetic number, because the mean of its divisors is an integer number (19993068966).

Almost surely, 2^66643563215 is an apocalyptic number.

66643563215 is a deficient number, since it is larger than the sum of its proper divisors (13328712649).

66643563215 is a wasteful number, since it uses less digits than its factorization.

66643563215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13328712648.

The product of its digits is 2332800, while the sum is 47.

The spelling of 66643563215 in words is "sixty-six billion, six hundred forty-three million, five hundred sixty-three thousand, two hundred fifteen".