66394309 has 2 divisors, whose sum is σ = 66394310. Its totient is φ = 66394308.

The previous prime is 66394277. The next prime is 66394351. The reversal of 66394309 is 90349366.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39125025 + 27269284 = 6255^2 + 5222^2 .

It is a cyclic number.

It is not a de Polignac number, because 66394309 - 2⁵ = 66394277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66391309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33197154 + 33197155.

It is an arithmetic number, because the mean of its divisors is an integer number (33197155).

Almost surely, 2^66394309 is an apocalyptic number.

It is an amenable number.

66394309 is a deficient number, since it is larger than the sum of its proper divisors (1).

66394309 is an equidigital number, since it uses as much as digits as its factorization.

66394309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 104976, while the sum is 40.

The square root of 66394309 is about 8148.2703072493. The cubic root of 66394309 is about 404.9272012626.

The spelling of 66394309 in words is "sixty-six million, three hundred ninety-four thousand, three hundred nine".