66231817 has 2 divisors, whose sum is σ = 66231818. Its totient is φ = 66231816.

The previous prime is 66231811. The next prime is 66231829. The reversal of 66231817 is 71813266.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 43086096 + 23145721 = 6564^2 + 4811^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66231817 is a prime.

It is not a weakly prime, because it can be changed into another prime (66231811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33115908 + 33115909.

It is an arithmetic number, because the mean of its divisors is an integer number (33115909).

Almost surely, 2^66231817 is an apocalyptic number.

It is an amenable number.

66231817 is a deficient number, since it is larger than the sum of its proper divisors (1).

66231817 is an equidigital number, since it uses as much as digits as its factorization.

66231817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 34.

The square root of 66231817 is about 8138.2932485872. The cubic root of 66231817 is about 404.5965947094.

The spelling of 66231817 in words is "sixty-six million, two hundred thirty-one thousand, eight hundred seventeen".