66697889 has 2 divisors, whose sum is σ = 66697890. Its totient is φ = 66697888.

The previous prime is 66697871. The next prime is 66697909. The reversal of 66697889 is 98879666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52128400 + 14569489 = 7220^2 + 3817^2 .

It is a cyclic number.

It is not a de Polignac number, because 66697889 - 2⁸ = 66697633 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66697819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33348944 + 33348945.

It is an arithmetic number, because the mean of its divisors is an integer number (33348945).

Almost surely, 2^66697889 is an apocalyptic number.

It is an amenable number.

66697889 is a deficient number, since it is larger than the sum of its proper divisors (1).

66697889 is an equidigital number, since it uses as much as digits as its factorization.

66697889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7838208, while the sum is 59.

The square root of 66697889 is about 8166.8775551002. The cubic root of 66697889 is about 405.5434233383.

The spelling of 66697889 in words is "sixty-six million, six hundred ninety-seven thousand, eight hundred eighty-nine".