18866857 has 2 divisors, whose sum is σ = 18866858. Its totient is φ = 18866856.

The previous prime is 18866851. The next prime is 18866863. The reversal of 18866857 is 75866881.

It is a balanced prime because it is at equal distance from previous prime (18866851) and next prime (18866863).

It can be written as a sum of positive squares in only one way, i.e., 10863616 + 8003241 = 3296^2 + 2829^2 .

It is an emirp because it is prime and its reverse (75866881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18866857 - 2¹¹ = 18864809 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18866857.

It is not a weakly prime, because it can be changed into another prime (18866851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9433428 + 9433429.

It is an arithmetic number, because the mean of its divisors is an integer number (9433429).

Almost surely, 2^18866857 is an apocalyptic number.

It is an amenable number.

18866857 is a deficient number, since it is larger than the sum of its proper divisors (1).

18866857 is an equidigital number, since it uses as much as digits as its factorization.

18866857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 645120, while the sum is 49.

The square root of 18866857 is about 4343.5995441569. The cubic root of 18866857 is about 266.2154067629.

The spelling of 18866857 in words is "eighteen million, eight hundred sixty-six thousand, eight hundred fifty-seven".