1009781909 has 2 divisors, whose sum is σ = 1009781910. Its totient is φ = 1009781908.

The previous prime is 1009781897. The next prime is 1009781933. The reversal of 1009781909 is 9091879001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 683979409 + 325802500 = 26153^2 + 18050^2 .

It is a cyclic number.

It is not a de Polignac number, because 1009781909 - 2⁴ = 1009781893 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1009781909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1009781209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 504890954 + 504890955.

It is an arithmetic number, because the mean of its divisors is an integer number (504890955).

Almost surely, 2^1009781909 is an apocalyptic number.

It is an amenable number.

1009781909 is a deficient number, since it is larger than the sum of its proper divisors (1).

1009781909 is an equidigital number, since it uses as much as digits as its factorization.

1009781909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40824, while the sum is 44.

The square root of 1009781909 is about 31777.0657707725. The cubic root of 1009781909 is about 1003.2500619871.

The spelling of 1009781909 in words is "one billion, nine million, seven hundred eighty-one thousand, nine hundred nine".