66216533 has 4 divisors (see below), whose sum is σ = 66233088. Its totient is φ = 66199980.

The previous prime is 66216511. The next prime is 66216551. The reversal of 66216533 is 33561266.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 33561266 = 2 ⋅16780633.

It is a cyclic number.

It is not a de Polignac number, because 66216533 - 2⁸ = 66216277 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 66216533.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66216583) 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, 1868 + ... + 11658.

It is an arithmetic number, because the mean of its divisors is an integer number (16558272).

Almost surely, 2^66216533 is an apocalyptic number.

It is an amenable number.

66216533 is a deficient number, since it is larger than the sum of its proper divisors (16555).

66216533 is an equidigital number, since it uses as much as digits as its factorization.

66216533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16554.

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

The square root of 66216533 is about 8137.3541768808. The cubic root of 66216533 is about 404.5654700407.

Adding to 66216533 its reverse (33561266), we get a palindrome (99777799).

The spelling of 66216533 in words is "sixty-six million, two hundred sixteen thousand, five hundred thirty-three".