1917385649 has 2 divisors, whose sum is σ = 1917385650. Its totient is φ = 1917385648.

The previous prime is 1917385607. The next prime is 1917385669. The reversal of 1917385649 is 9465837191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1665211249 + 252174400 = 40807^2 + 15880^2 .

It is a cyclic number.

It is not a de Polignac number, because 1917385649 - 2²⁴ = 1900608433 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1917385649.

It is not a weakly prime, because it can be changed into another prime (1917385669) 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, 958692824 + 958692825.

It is an arithmetic number, because the mean of its divisors is an integer number (958692825).

Almost surely, 2^1917385649 is an apocalyptic number.

It is an amenable number.

1917385649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1917385649 is an equidigital number, since it uses as much as digits as its factorization.

1917385649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1632960, while the sum is 53.

The square root of 1917385649 is about 43787.9623755205. The cubic root of 1917385649 is about 1242.3286213919.

The spelling of 1917385649 in words is "one billion, nine hundred seventeen million, three hundred eighty-five thousand, six hundred forty-nine".