66969989 has 2 divisors, whose sum is σ = 66969990. Its totient is φ = 66969988.

The previous prime is 66969977. The next prime is 66970039. The reversal of 66969989 is 98996966.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63473089 + 3496900 = 7967^2 + 1870^2 .

It is a cyclic number.

It is not a de Polignac number, because 66969989 - 2²⁴ = 50192773 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66969289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33484994 + 33484995.

It is an arithmetic number, because the mean of its divisors is an integer number (33484995).

Almost surely, 2^66969989 is an apocalyptic number.

It is an amenable number.

66969989 is a deficient number, since it is larger than the sum of its proper divisors (1).

66969989 is an equidigital number, since it uses as much as digits as its factorization.

66969989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11337408, while the sum is 62.

The square root of 66969989 is about 8183.5193529435. The cubic root of 66969989 is about 406.0941586396.

The spelling of 66969989 in words is "sixty-six million, nine hundred sixty-nine thousand, nine hundred eighty-nine".