67166221 has 2 divisors, whose sum is σ = 67166222. Its totient is φ = 67166220.

The previous prime is 67166207. The next prime is 67166251. The reversal of 67166221 is 12266176.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64561225 + 2604996 = 8035^2 + 1614^2 .

It is a cyclic number.

It is not a de Polignac number, because 67166221 - 2¹¹ = 67164173 is a prime.

It is a super-2 number, since 2×67166221² = 9022602486841682, which contains 22 as substring.

It is a Chen prime.

It is the 8196-th Hogben number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (67166251) by changing a digit.

It is a nontrivial repunit in base 8195.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33583110 + 33583111.

It is an arithmetic number, because the mean of its divisors is an integer number (33583111).

Almost surely, 2^67166221 is an apocalyptic number.

It is an amenable number.

67166221 is a deficient number, since it is larger than the sum of its proper divisors (1).

67166221 is an equidigital number, since it uses as much as digits as its factorization.

67166221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6048, while the sum is 31.

The square root of 67166221 is about 8195.5000457568. The cubic root of 67166221 is about 406.4904105697.

The spelling of 67166221 in words is "sixty-seven million, one hundred sixty-six thousand, two hundred twenty-one".