66405799 has 2 divisors, whose sum is σ = 66405800. Its totient is φ = 66405798.

The previous prime is 66405797. The next prime is 66405821. The reversal of 66405799 is 99750466.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66405799 - 2¹ = 66405797 is a prime.

Together with 66405797, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66405797) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33202899 + 33202900.

It is an arithmetic number, because the mean of its divisors is an integer number (33202900).

Almost surely, 2^66405799 is an apocalyptic number.

66405799 is a deficient number, since it is larger than the sum of its proper divisors (1).

66405799 is an equidigital number, since it uses as much as digits as its factorization.

66405799 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 408240, while the sum is 46.

The square root of 66405799 is about 8148.9753343595. The cubic root of 66405799 is about 404.9505584110.

The spelling of 66405799 in words is "sixty-six million, four hundred five thousand, seven hundred ninety-nine".