1813779761 has 2 divisors, whose sum is σ = 1813779762. Its totient is φ = 1813779760.

The previous prime is 1813779749. The next prime is 1813779769. The reversal of 1813779761 is 1679773181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1015378225 + 798401536 = 31865^2 + 28256^2 .

It is an emirp because it is prime and its reverse (1679773181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1813779761 - 2²² = 1809585457 is a prime.

It is not a weakly prime, because it can be changed into another prime (1813779769) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 906889880 + 906889881.

It is an arithmetic number, because the mean of its divisors is an integer number (906889881).

Almost surely, 2^1813779761 is an apocalyptic number.

It is an amenable number.

1813779761 is a deficient number, since it is larger than the sum of its proper divisors (1).

1813779761 is an equidigital number, since it uses as much as digits as its factorization.

1813779761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 444528, while the sum is 50.

The square root of 1813779761 is about 42588.4932933768. The cubic root of 1813779761 is about 1219.5366333570.

The spelling of 1813779761 in words is "one billion, eight hundred thirteen million, seven hundred seventy-nine thousand, seven hundred sixty-one".