66211623 has 6 divisors (see below), whose sum is σ = 95639024. Its totient is φ = 44141076.

The previous prime is 66211619. The next prime is 66211627. The reversal of 66211623 is 32611266.

66211623 is a `hidden beast` number, since 6 + 621 + 16 + 23 = 666.

It is an interprime number because it is at equal distance from previous prime (66211619) and next prime (66211627).

It is not a de Polignac number, because 66211623 - 2² = 66211619 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 (66211627) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3678415 + ... + 3678432.

Almost surely, 2^66211623 is an apocalyptic number.

66211623 is a deficient number, since it is larger than the sum of its proper divisors (29427401).

66211623 is a wasteful number, since it uses less digits than its factorization.

66211623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7356853 (or 7356850 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 66211623 is about 8137.0524761734. The cubic root of 66211623 is about 404.5554701939. Note that the first 3 decimals are identical.

Adding to 66211623 its reverse (32611266), we get a palindrome (98822889).

The spelling of 66211623 in words is "sixty-six million, two hundred eleven thousand, six hundred twenty-three".