18436861 has 2 divisors, whose sum is σ = 18436862. Its totient is φ = 18436860.

The previous prime is 18436829. The next prime is 18436871. The reversal of 18436861 is 16863481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18404100 + 32761 = 4290^2 + 181^2 .

It is an emirp because it is prime and its reverse (16863481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18436861 - 2⁵ = 18436829 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18436861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18436801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9218430 + 9218431.

It is an arithmetic number, because the mean of its divisors is an integer number (9218431).

Almost surely, 2^18436861 is an apocalyptic number.

It is an amenable number.

18436861 is a deficient number, since it is larger than the sum of its proper divisors (1).

18436861 is an equidigital number, since it uses as much as digits as its factorization.

18436861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27648, while the sum is 37.

The square root of 18436861 is about 4293.8166006480. The cubic root of 18436861 is about 264.1773993236.

The spelling of 18436861 in words is "eighteen million, four hundred thirty-six thousand, eight hundred sixty-one".