66388823 has 4 divisors (see below), whose sum is σ = 66424128. Its totient is φ = 66353520.

The previous prime is 66388783. The next prime is 66388849. The reversal of 66388823 is 32888366.

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 66388823 - 2²² = 62194519 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 (66388853) 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, 14663 + ... + 18648.

It is an arithmetic number, because the mean of its divisors is an integer number (16606032).

Almost surely, 2^66388823 is an apocalyptic number.

66388823 is a deficient number, since it is larger than the sum of its proper divisors (35305).

66388823 is a wasteful number, since it uses less digits than its factorization.

66388823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35304.

The product of its digits is 331776, while the sum is 44.

The square root of 66388823 is about 8147.9336644330. The cubic root of 66388823 is about 404.9160482394.

The spelling of 66388823 in words is "sixty-six million, three hundred eighty-eight thousand, eight hundred twenty-three".