66486991 has 2 divisors, whose sum is σ = 66486992. Its totient is φ = 66486990.

The previous prime is 66486941. The next prime is 66487009. The reversal of 66486991 is 19968466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66486991 - 2⁷ = 66486863 is a prime.

It is a Chen prime.

It is a zygodrome in base 3.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66486941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33243495 + 33243496.

It is an arithmetic number, because the mean of its divisors is an integer number (33243496).

Almost surely, 2^66486991 is an apocalyptic number.

66486991 is a deficient number, since it is larger than the sum of its proper divisors (1).

66486991 is an equidigital number, since it uses as much as digits as its factorization.

66486991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 49.

The square root of 66486991 is about 8153.9555431704. The cubic root of 66486991 is about 405.1155307248.

The spelling of 66486991 in words is "sixty-six million, four hundred eighty-six thousand, nine hundred ninety-one".