6645166309 has 2 divisors, whose sum is σ = 6645166310. Its totient is φ = 6645166308.

The previous prime is 6645166301. The next prime is 6645166453. The reversal of 6645166309 is 9036615466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4349798209 + 2295368100 = 65953^2 + 47910^2 .

It is a cyclic number.

It is not a de Polignac number, because 6645166309 - 2³ = 6645166301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6645166301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3322583154 + 3322583155.

It is an arithmetic number, because the mean of its divisors is an integer number (3322583155).

Almost surely, 2^6645166309 is an apocalyptic number.

It is an amenable number.

6645166309 is a deficient number, since it is larger than the sum of its proper divisors (1).

6645166309 is an equidigital number, since it uses as much as digits as its factorization.

6645166309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 699840, while the sum is 46.

The square root of 6645166309 is about 81517.8895028570. The cubic root of 6645166309 is about 1880.0466176949.

The spelling of 6645166309 in words is "six billion, six hundred forty-five million, one hundred sixty-six thousand, three hundred nine".