66923209 has 2 divisors, whose sum is σ = 66923210. Its totient is φ = 66923208.

The previous prime is 66923183. The next prime is 66923249. The reversal of 66923209 is 90232966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48260809 + 18662400 = 6947^2 + 4320^2 .

It is a cyclic number.

It is not a de Polignac number, because 66923209 - 2⁵ = 66923177 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66923249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33461604 + 33461605.

It is an arithmetic number, because the mean of its divisors is an integer number (33461605).

Almost surely, 2^66923209 is an apocalyptic number.

It is an amenable number.

66923209 is a deficient number, since it is larger than the sum of its proper divisors (1).

66923209 is an equidigital number, since it uses as much as digits as its factorization.

66923209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 37.

The square root of 66923209 is about 8180.6606701415. The cubic root of 66923209 is about 405.9995814017. Note that the first 3 decimals are identical.

The spelling of 66923209 in words is "sixty-six million, nine hundred twenty-three thousand, two hundred nine".