66181387 has 2 divisors, whose sum is σ = 66181388. Its totient is φ = 66181386.

The previous prime is 66181363. The next prime is 66181397. The reversal of 66181387 is 78318166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66181387 - 2¹⁹ = 65657099 is a prime.

It is not a weakly prime, because it can be changed into another prime (66181307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33090693 + 33090694.

It is an arithmetic number, because the mean of its divisors is an integer number (33090694).

Almost surely, 2^66181387 is an apocalyptic number.

66181387 is a deficient number, since it is larger than the sum of its proper divisors (1).

66181387 is an equidigital number, since it uses as much as digits as its factorization.

66181387 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 40.

The square root of 66181387 is about 8135.1943430996. The cubic root of 66181387 is about 404.4938797908.

The spelling of 66181387 in words is "sixty-six million, one hundred eighty-one thousand, three hundred eighty-seven".