66836881 has 2 divisors, whose sum is σ = 66836882. Its totient is φ = 66836880.

The previous prime is 66836863. The next prime is 66836933. The reversal of 66836881 is 18863866.

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., 60980481 + 5856400 = 7809^2 + 2420^2 .

It is a cyclic number.

It is not a de Polignac number, because 66836881 - 2⁵ = 66836849 is a prime.

It is a super-2 number, since 2×66836881² = 8934337323616322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66836831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33418440 + 33418441.

It is an arithmetic number, because the mean of its divisors is an integer number (33418441).

Almost surely, 2^66836881 is an apocalyptic number.

It is an amenable number.

66836881 is a deficient number, since it is larger than the sum of its proper divisors (1).

66836881 is an equidigital number, since it uses as much as digits as its factorization.

66836881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 331776, while the sum is 46.

The square root of 66836881 is about 8175.3826210154. The cubic root of 66836881 is about 405.8249324082.

The spelling of 66836881 in words is "sixty-six million, eight hundred thirty-six thousand, eight hundred eighty-one".