66388933 has 4 divisors (see below), whose sum is σ = 71495788. Its totient is φ = 61282080.

The previous prime is 66388919. The next prime is 66388937. The reversal of 66388933 is 33988366.

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

It can be written as a sum of positive squares in 2 ways, for example, as 22591009 + 43797924 = 4753^2 + 6618^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66388933 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66388937) 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, 2553408 + ... + 2553433.

It is an arithmetic number, because the mean of its divisors is an integer number (17873947).

Almost surely, 2^66388933 is an apocalyptic number.

It is an amenable number.

66388933 is a deficient number, since it is larger than the sum of its proper divisors (5106855).

66388933 is a wasteful number, since it uses less digits than its factorization.

66388933 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5106854.

The product of its digits is 559872, while the sum is 46.

The square root of 66388933 is about 8147.9404146079. The cubic root of 66388933 is about 404.9162718751.

The spelling of 66388933 in words is "sixty-six million, three hundred eighty-eight thousand, nine hundred thirty-three".