66817427 has 4 divisors (see below), whose sum is σ = 66984456. Its totient is φ = 66650400.

The previous prime is 66817393. The next prime is 66817447. The reversal of 66817427 is 72471866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 72471866 = 2 ⋅36235933.

It is a cyclic number.

It is not a de Polignac number, because 66817427 - 2⁸ = 66817171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66817447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82913 + ... + 83714.

It is an arithmetic number, because the mean of its divisors is an integer number (16746114).

Almost surely, 2^66817427 is an apocalyptic number.

66817427 is a deficient number, since it is larger than the sum of its proper divisors (167029).

66817427 is a wasteful number, since it uses less digits than its factorization.

66817427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167028.

The product of its digits is 112896, while the sum is 41.

The square root of 66817427 is about 8174.1927430175. The cubic root of 66817427 is about 405.7855545267.

The spelling of 66817427 in words is "sixty-six million, eight hundred seventeen thousand, four hundred twenty-seven".