6940509209 has 2 divisors, whose sum is σ = 6940509210. Its totient is φ = 6940509208.

The previous prime is 6940509197. The next prime is 6940509217. The reversal of 6940509209 is 9029050496.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6678975625 + 261533584 = 81725^2 + 16172^2 .

It is a cyclic number.

It is not a de Polignac number, because 6940509209 - 2¹⁶ = 6940443673 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6940509209.

It is not a weakly prime, because it can be changed into another prime (6940509229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3470254604 + 3470254605.

It is an arithmetic number, because the mean of its divisors is an integer number (3470254605).

Almost surely, 2^6940509209 is an apocalyptic number.

It is an amenable number.

6940509209 is a deficient number, since it is larger than the sum of its proper divisors (1).

6940509209 is an equidigital number, since it uses as much as digits as its factorization.

6940509209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 174960, while the sum is 44.

The square root of 6940509209 is about 83309.7185747257. The cubic root of 6940509209 is about 1907.4966252237.

The spelling of 6940509209 in words is "six billion, nine hundred forty million, five hundred nine thousand, two hundred nine".