66189889 has 2 divisors, whose sum is σ = 66189890. Its totient is φ = 66189888.

The previous prime is 66189887. The next prime is 66189911. The reversal of 66189889 is 98898166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66178225 + 11664 = 8135^2 + 108^2 .

It is a cyclic number.

It is not a de Polignac number, because 66189889 - 2¹ = 66189887 is a prime.

It is a super-2 number, since 2×66189889² = 8762202811664642, which contains 22 as substring.

Together with 66189887, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (66189887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33094944 + 33094945.

It is an arithmetic number, because the mean of its divisors is an integer number (33094945).

Almost surely, 2^66189889 is an apocalyptic number.

It is an amenable number.

66189889 is a deficient number, since it is larger than the sum of its proper divisors (1).

66189889 is an equidigital number, since it uses as much as digits as its factorization.

66189889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1492992, while the sum is 55.

The square root of 66189889 is about 8135.7168706882. The cubic root of 66189889 is about 404.5112001678.

The spelling of 66189889 in words is "sixty-six million, one hundred eighty-nine thousand, eight hundred eighty-nine".