18700861 has 2 divisors, whose sum is σ = 18700862. Its totient is φ = 18700860.

The previous prime is 18700859. The next prime is 18700889. The reversal of 18700861 is 16800781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12916836 + 5784025 = 3594^2 + 2405^2 .

It is a cyclic number.

It is not a de Polignac number, because 18700861 - 2¹ = 18700859 is a prime.

Together with 18700859, it forms a pair of twin primes.

It is equal to p_1193179 and since 18700861 and 1193179 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18700061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9350430 + 9350431.

It is an arithmetic number, because the mean of its divisors is an integer number (9350431).

Almost surely, 2^18700861 is an apocalyptic number.

It is an amenable number.

18700861 is a deficient number, since it is larger than the sum of its proper divisors (1).

18700861 is an equidigital number, since it uses as much as digits as its factorization.

18700861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2688, while the sum is 31.

The square root of 18700861 is about 4324.4492134837. The cubic root of 18700861 is about 265.4323593505.

The spelling of 18700861 in words is "eighteen million, seven hundred thousand, eight hundred sixty-one".