66215633 has 4 divisors (see below), whose sum is σ = 72235248. Its totient is φ = 60196020.

The previous prime is 66215623. The next prime is 66215693. The reversal of 66215633 is 33651266.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66215633 - 2²⁰ = 65167057 is a prime.

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 66215633.

It is not an unprimeable number, because it can be changed into a prime (66215623) 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, 3009791 + ... + 3009812.

It is an arithmetic number, because the mean of its divisors is an integer number (18058812).

Almost surely, 2^66215633 is an apocalyptic number.

It is an amenable number.

66215633 is a deficient number, since it is larger than the sum of its proper divisors (6019615).

66215633 is a wasteful number, since it uses less digits than its factorization.

66215633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6019614.

The product of its digits is 19440, while the sum is 32.

The square root of 66215633 is about 8137.2988761628. The cubic root of 66215633 is about 404.5636371119.

Adding to 66215633 its reverse (33651266), we get a palindrome (99866899).

The spelling of 66215633 in words is "sixty-six million, two hundred fifteen thousand, six hundred thirty-three".