18686461 has 2 divisors, whose sum is σ = 18686462. Its totient is φ = 18686460.

The previous prime is 18686449. The next prime is 18686491. The reversal of 18686461 is 16468681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17724100 + 962361 = 4210^2 + 981^2 .

It is an emirp because it is prime and its reverse (16468681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18686461 - 2¹³ = 18678269 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18686431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9343230 + 9343231.

It is an arithmetic number, because the mean of its divisors is an integer number (9343231).

Almost surely, 2^18686461 is an apocalyptic number.

It is an amenable number.

18686461 is a deficient number, since it is larger than the sum of its proper divisors (1).

18686461 is an equidigital number, since it uses as much as digits as its factorization.

18686461 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55296, while the sum is 40.

The square root of 18686461 is about 4322.7839409344. The cubic root of 18686461 is about 265.3642126226.

The spelling of 18686461 in words is "eighteen million, six hundred eighty-six thousand, four hundred sixty-one".