76840409 has 2 divisors, whose sum is σ = 76840410. Its totient is φ = 76840408.

The previous prime is 76840399. The next prime is 76840411. The reversal of 76840409 is 90404867.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41473600 + 35366809 = 6440^2 + 5947^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-76840409 is a prime.

It is a Sophie Germain prime.

Together with 76840411, 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 (76840609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38420204 + 38420205.

It is an arithmetic number, because the mean of its divisors is an integer number (38420205).

Almost surely, 2^76840409 is an apocalyptic number.

It is an amenable number.

76840409 is a deficient number, since it is larger than the sum of its proper divisors (1).

76840409 is an equidigital number, since it uses as much as digits as its factorization.

76840409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48384, while the sum is 38.

The square root of 76840409 is about 8765.8661294820. The cubic root of 76840409 is about 425.1379648971.

The spelling of 76840409 in words is "seventy-six million, eight hundred forty thousand, four hundred nine".