66173879 has 2 divisors, whose sum is σ = 66173880. Its totient is φ = 66173878.

The previous prime is 66173873. The next prime is 66173897. The reversal of 66173879 is 97837166.

Together with next prime (66173897) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66173879 - 2²⁰ = 65125303 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66173873) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33086939 + 33086940.

It is an arithmetic number, because the mean of its divisors is an integer number (33086940).

Almost surely, 2^66173879 is an apocalyptic number.

66173879 is a deficient number, since it is larger than the sum of its proper divisors (1).

66173879 is an equidigital number, since it uses as much as digits as its factorization.

66173879 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 381024, while the sum is 47.

The square root of 66173879 is about 8134.7328782204. The cubic root of 66173879 is about 404.4785831693.

The spelling of 66173879 in words is "sixty-six million, one hundred seventy-three thousand, eight hundred seventy-nine".