66220181 has 2 divisors, whose sum is σ = 66220182. Its totient is φ = 66220180.

The previous prime is 66220169. The next prime is 66220199. The reversal of 66220181 is 18102266.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64657681 + 1562500 = 8041^2 + 1250^2 .

It is a cyclic number.

It is not a de Polignac number, because 66220181 - 2¹⁸ = 65958037 is a prime.

It is a super-2 number, since 2×66220181² = 8770224743345522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 66220181.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66220081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33110090 + 33110091.

It is an arithmetic number, because the mean of its divisors is an integer number (33110091).

Almost surely, 2^66220181 is an apocalyptic number.

It is an amenable number.

66220181 is a deficient number, since it is larger than the sum of its proper divisors (1).

66220181 is an equidigital number, since it uses as much as digits as its factorization.

66220181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 66220181 is about 8137.5783252759. The cubic root of 66220181 is about 404.5728993420.

The spelling of 66220181 in words is "sixty-six million, two hundred twenty thousand, one hundred eighty-one".