1813685161 has 2 divisors, whose sum is σ = 1813685162. Its totient is φ = 1813685160.

The previous prime is 1813685063. The next prime is 1813685173. The reversal of 1813685161 is 1615863181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1424609536 + 389075625 = 37744^2 + 19725^2 .

It is an emirp because it is prime and its reverse (1615863181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1813685161 - 2¹⁷ = 1813554089 is a prime.

It is not a weakly prime, because it can be changed into another prime (1813695161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 906842580 + 906842581.

It is an arithmetic number, because the mean of its divisors is an integer number (906842581).

Almost surely, 2^1813685161 is an apocalyptic number.

It is an amenable number.

1813685161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1813685161 is an equidigital number, since it uses as much as digits as its factorization.

1813685161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34560, while the sum is 40.

The square root of 1813685161 is about 42587.3826502639. The cubic root of 1813685161 is about 1219.5154308248.

The spelling of 1813685161 in words is "one billion, eight hundred thirteen million, six hundred eighty-five thousand, one hundred sixty-one".