66816279 has 8 divisors (see below), whose sum is σ = 98987120. Its totient is φ = 44544168.

The previous prime is 66816271. The next prime is 66816283. The reversal of 66816279 is 97261866.

It is not a de Polignac number, because 66816279 - 2³ = 66816271 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 (66816271) 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, 1237312 + ... + 1237365.

It is an arithmetic number, because the mean of its divisors is an integer number (12373390).

Almost surely, 2^66816279 is an apocalyptic number.

66816279 is a deficient number, since it is larger than the sum of its proper divisors (32170841).

66816279 is a wasteful number, since it uses less digits than its factorization.

66816279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2474686 (or 2474680 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The square root of 66816279 is about 8174.1225217145. The cubic root of 66816279 is about 405.7832305597.

The spelling of 66816279 in words is "sixty-six million, eight hundred sixteen thousand, two hundred seventy-nine".