66173213 has 2 divisors, whose sum is σ = 66173214. Its totient is φ = 66173212.

The previous prime is 66173147. The next prime is 66173297. The reversal of 66173213 is 31237166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39413284 + 26759929 = 6278^2 + 5173^2 .

It is a cyclic number.

It is not a de Polignac number, because 66173213 - 2¹⁰ = 66172189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66173413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33086606 + 33086607.

It is an arithmetic number, because the mean of its divisors is an integer number (33086607).

Almost surely, 2^66173213 is an apocalyptic number.

It is an amenable number.

66173213 is a deficient number, since it is larger than the sum of its proper divisors (1).

66173213 is an equidigital number, since it uses as much as digits as its factorization.

66173213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 29.

The square root of 66173213 is about 8134.6919425385. The cubic root of 66173213 is about 404.4772262207.

The spelling of 66173213 in words is "sixty-six million, one hundred seventy-three thousand, two hundred thirteen".