1861694117 has 2 divisors, whose sum is σ = 1861694118. Its totient is φ = 1861694116.

The previous prime is 1861694047. The next prime is 1861694141. The reversal of 1861694117 is 7114961681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 953636161 + 908057956 = 30881^2 + 30134^2 .

It is an emirp because it is prime and its reverse (7114961681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1861694117 - 2²⁶ = 1794585253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1861694147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 930847058 + 930847059.

It is an arithmetic number, because the mean of its divisors is an integer number (930847059).

Almost surely, 2^1861694117 is an apocalyptic number.

It is an amenable number.

1861694117 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861694117 is an equidigital number, since it uses as much as digits as its factorization.

1861694117 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 44.

The square root of 1861694117 is about 43147.3535341393. The cubic root of 1861694117 is about 1230.1822095500.

The spelling of 1861694117 in words is "one billion, eight hundred sixty-one million, six hundred ninety-four thousand, one hundred seventeen".