18679861 has 2 divisors, whose sum is σ = 18679862. Its totient is φ = 18679860.

The previous prime is 18679823. The next prime is 18679873. The reversal of 18679861 is 16897681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11492100 + 7187761 = 3390^2 + 2681^2 .

It is a cyclic number.

It is not a de Polignac number, because 18679861 - 2¹⁵ = 18647093 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 (18679811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9339930 + 9339931.

It is an arithmetic number, because the mean of its divisors is an integer number (9339931).

Almost surely, 2^18679861 is an apocalyptic number.

It is an amenable number.

18679861 is a deficient number, since it is larger than the sum of its proper divisors (1).

18679861 is an equidigital number, since it uses as much as digits as its factorization.

18679861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 46.

The square root of 18679861 is about 4322.0204765827. The cubic root of 18679861 is about 265.3329670051.

The spelling of 18679861 in words is "eighteen million, six hundred seventy-nine thousand, eight hundred sixty-one".