66090209 has 2 divisors, whose sum is σ = 66090210. Its totient is φ = 66090208.

The previous prime is 66090187. The next prime is 66090221. The reversal of 66090209 is 90209066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44930209 + 21160000 = 6703^2 + 4600^2 .

It is a cyclic number.

It is not a de Polignac number, because 66090209 - 2¹² = 66086113 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66090229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33045104 + 33045105.

It is an arithmetic number, because the mean of its divisors is an integer number (33045105).

Almost surely, 2^66090209 is an apocalyptic number.

It is an amenable number.

66090209 is a deficient number, since it is larger than the sum of its proper divisors (1).

66090209 is an equidigital number, since it uses as much as digits as its factorization.

66090209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 32.

The square root of 66090209 is about 8129.5884889704. The cubic root of 66090209 is about 404.3080375445.

The spelling of 66090209 in words is "sixty-six million, ninety thousand, two hundred nine".