840409001 has 2 divisors, whose sum is σ = 840409002. Its totient is φ = 840409000.

The previous prime is 840408979. The next prime is 840409013. The reversal of 840409001 is 100904048.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 499969600 + 340439401 = 22360^2 + 18451^2 .

It is a cyclic number.

It is not a de Polignac number, because 840409001 - 2²² = 836214697 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (840409051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420204500 + 420204501.

It is an arithmetic number, because the mean of its divisors is an integer number (420204501).

Almost surely, 2^840409001 is an apocalyptic number.

It is an amenable number.

840409001 is a deficient number, since it is larger than the sum of its proper divisors (1).

840409001 is an equidigital number, since it uses as much as digits as its factorization.

840409001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 840409001 is about 28989.8085712893. The cubic root of 840409001 is about 943.6919094341.

The spelling of 840409001 in words is "eight hundred forty million, four hundred nine thousand, one".