66157181 has 2 divisors, whose sum is σ = 66157182. Its totient is φ = 66157180.

The previous prime is 66157159. The next prime is 66157211. The reversal of 66157181 is 18175166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49420900 + 16736281 = 7030^2 + 4091^2 .

It is a cyclic number.

It is not a de Polignac number, because 66157181 - 2²² = 61962877 is a prime.

It is a super-2 number, since 2×66157181² = 8753545195733522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66157111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33078590 + 33078591.

It is an arithmetic number, because the mean of its divisors is an integer number (33078591).

Almost surely, 2^66157181 is an apocalyptic number.

It is an amenable number.

66157181 is a deficient number, since it is larger than the sum of its proper divisors (1).

66157181 is an equidigital number, since it uses as much as digits as its factorization.

66157181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10080, while the sum is 35.

The square root of 66157181 is about 8133.7064736810. The cubic root of 66157181 is about 404.4445589105. Note that the first 3 decimals are identical.

The spelling of 66157181 in words is "sixty-six million, one hundred fifty-seven thousand, one hundred eighty-one".