66380399 has 2 divisors, whose sum is σ = 66380400. Its totient is φ = 66380398.

The previous prime is 66380387. The next prime is 66380401. The reversal of 66380399 is 99308366.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66380399 - 2⁸ = 66380143 is a prime.

It is a Sophie Germain prime.

Together with 66380401, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66385399) 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, 33190199 + 33190200.

It is an arithmetic number, because the mean of its divisors is an integer number (33190200).

Almost surely, 2^66380399 is an apocalyptic number.

66380399 is a deficient number, since it is larger than the sum of its proper divisors (1).

66380399 is an equidigital number, since it uses as much as digits as its factorization.

66380399 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 209952, while the sum is 44.

The square root of 66380399 is about 8147.4167071533. The cubic root of 66380399 is about 404.8989210739.

The spelling of 66380399 in words is "sixty-six million, three hundred eighty thousand, three hundred ninety-nine".