66996997 has 2 divisors, whose sum is σ = 66996998. Its totient is φ = 66996996.

The previous prime is 66996961. The next prime is 66997009. The reversal of 66996997 is 79969966.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66569281 + 427716 = 8159^2 + 654^2 .

It is a cyclic number.

It is not a de Polignac number, because 66996997 - 2¹⁵ = 66964229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66996947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33498498 + 33498499.

It is an arithmetic number, because the mean of its divisors is an integer number (33498499).

Almost surely, 2^66996997 is an apocalyptic number.

It is an amenable number.

66996997 is a deficient number, since it is larger than the sum of its proper divisors (1).

66996997 is an equidigital number, since it uses as much as digits as its factorization.

66996997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9920232, while the sum is 61.

The square root of 66996997 is about 8185.1693323962. The cubic root of 66996997 is about 406.1487418798.

The spelling of 66996997 in words is "sixty-six million, nine hundred ninety-six thousand, nine hundred ninety-seven".