66216638 has 8 divisors (see below), whose sum is σ = 99428160. Its totient is φ = 33073920.

The previous prime is 66216637. The next prime is 66216641. The reversal of 66216638 is 83661266.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66216637) 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, 14723 + ... + 18686.

It is an arithmetic number, because the mean of its divisors is an integer number (12428520).

Almost surely, 2^66216638 is an apocalyptic number.

66216638 is a deficient number, since it is larger than the sum of its proper divisors (33211522).

66216638 is a wasteful number, since it uses less digits than its factorization.

66216638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34402.

The product of its digits is 62208, while the sum is 38.

The square root of 66216638 is about 8137.3606286068. The cubic root of 66216638 is about 404.5656838813.

The spelling of 66216638 in words is "sixty-six million, two hundred sixteen thousand, six hundred thirty-eight".