66609769 has 2 divisors, whose sum is σ = 66609770. Its totient is φ = 66609768.

The previous prime is 66609733. The next prime is 66609779. The reversal of 66609769 is 96790666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64593369 + 2016400 = 8037^2 + 1420^2 .

It is a cyclic number.

It is not a de Polignac number, because 66609769 - 2¹⁷ = 66478697 is a prime.

It is a super-2 number, since 2×66609769² = 8873722652466722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66609779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33304884 + 33304885.

It is an arithmetic number, because the mean of its divisors is an integer number (33304885).

Almost surely, 2^66609769 is an apocalyptic number.

It is an amenable number.

66609769 is a deficient number, since it is larger than the sum of its proper divisors (1).

66609769 is an equidigital number, since it uses as much as digits as its factorization.

66609769 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 734832, while the sum is 49.

The square root of 66609769 is about 8161.4808092649. The cubic root of 66609769 is about 405.3647458384.

The spelling of 66609769 in words is "sixty-six million, six hundred nine thousand, seven hundred sixty-nine".