1865912861 has 2 divisors, whose sum is σ = 1865912862. Its totient is φ = 1865912860.

The previous prime is 1865912827. The next prime is 1865912863. The reversal of 1865912861 is 1682195681.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1779236761 + 86676100 = 42181^2 + 9310^2 .

It is an emirp because it is prime and its reverse (1682195681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1865912861 - 2¹⁰ = 1865911837 is a prime.

It is a Sophie Germain prime.

Together with 1865912863, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1865912863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 932956430 + 932956431.

It is an arithmetic number, because the mean of its divisors is an integer number (932956431).

Almost surely, 2^1865912861 is an apocalyptic number.

It is an amenable number.

1865912861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1865912861 is an equidigital number, since it uses as much as digits as its factorization.

1865912861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 207360, while the sum is 47.

The square root of 1865912861 is about 43196.2135030375. The cubic root of 1865912861 is about 1231.1107381259.

The spelling of 1865912861 in words is "one billion, eight hundred sixty-five million, nine hundred twelve thousand, eight hundred sixty-one".