340728809 has 2 divisors, whose sum is σ = 340728810. Its totient is φ = 340728808.

The previous prime is 340728763. The next prime is 340728811. The reversal of 340728809 is 908827043.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 234947584 + 105781225 = 15328^2 + 10285^2 .

It is an emirp because it is prime and its reverse (908827043) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-340728809 is a prime.

It is a super-2 number, since 2×340728809² = 232192242565116962, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 340728811, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (340728889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 170364404 + 170364405.

It is an arithmetic number, because the mean of its divisors is an integer number (170364405).

Almost surely, 2^340728809 is an apocalyptic number.

It is an amenable number.

340728809 is a deficient number, since it is larger than the sum of its proper divisors (1).

340728809 is an equidigital number, since it uses as much as digits as its factorization.

340728809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96768, while the sum is 41.

The square root of 340728809 is about 18458.8409441113. The cubic root of 340728809 is about 698.4515493496.

The spelling of 340728809 in words is "three hundred forty million, seven hundred twenty-eight thousand, eight hundred nine".