66216813 has 8 divisors (see below), whose sum is σ = 95080608. Its totient is φ = 40748784.

The previous prime is 66216811. The next prime is 66216823. The reversal of 66216813 is 31861266.

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

It is not a de Polignac number, because 66216813 - 2¹ = 66216811 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66216811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 848895 + ... + 848972.

It is an arithmetic number, because the mean of its divisors is an integer number (11885076).

Almost surely, 2^66216813 is an apocalyptic number.

It is an amenable number.

66216813 is a deficient number, since it is larger than the sum of its proper divisors (28863795).

66216813 is a wasteful number, since it uses less digits than its factorization.

66216813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1697883.

The product of its digits is 10368, while the sum is 33.

The square root of 66216813 is about 8137.3713814720. The cubic root of 66216813 is about 404.5660402818.

The spelling of 66216813 in words is "sixty-six million, two hundred sixteen thousand, eight hundred thirteen".