66816523 has 2 divisors, whose sum is σ = 66816524. Its totient is φ = 66816522.

The previous prime is 66816509. The next prime is 66816553. The reversal of 66816523 is 32561866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66816523 - 2⁹ = 66816011 is a prime.

It is equal to p_3941596 and since 66816523 and 3941596 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (66816553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33408261 + 33408262.

It is an arithmetic number, because the mean of its divisors is an integer number (33408262).

Almost surely, 2^66816523 is an apocalyptic number.

66816523 is a deficient number, since it is larger than the sum of its proper divisors (1).

66816523 is an equidigital number, since it uses as much as digits as its factorization.

66816523 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 37.

The square root of 66816523 is about 8174.1374468503. The cubic root of 66816523 is about 405.7837245061.

The spelling of 66816523 in words is "sixty-six million, eight hundred sixteen thousand, five hundred twenty-three".