1217825809 has 2 divisors, whose sum is σ = 1217825810. Its totient is φ = 1217825808.

The previous prime is 1217825801. The next prime is 1217825813. The reversal of 1217825809 is 9085287121.

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., 910349584 + 307476225 = 30172^2 + 17535^2 .

It is a cyclic number.

It is not a de Polignac number, because 1217825809 - 2³ = 1217825801 is a prime.

It is not a weakly prime, because it can be changed into another prime (1217825801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608912904 + 608912905.

It is an arithmetic number, because the mean of its divisors is an integer number (608912905).

Almost surely, 2^1217825809 is an apocalyptic number.

It is an amenable number.

1217825809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1217825809 is an equidigital number, since it uses as much as digits as its factorization.

1217825809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 80640, while the sum is 43.

The square root of 1217825809 is about 34897.3610606877. The cubic root of 1217825809 is about 1067.8946019631.

The spelling of 1217825809 in words is "one billion, two hundred seventeen million, eight hundred twenty-five thousand, eight hundred nine".