18861881 has 2 divisors, whose sum is σ = 18861882. Its totient is φ = 18861880.

The previous prime is 18861827. The next prime is 18861893. The reversal of 18861881 is 18816881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9765625 + 9096256 = 3125^2 + 3016^2 .

It is a cyclic number.

It is not a de Polignac number, because 18861881 - 2¹⁰ = 18860857 is a prime.

It is a super-2 number, since 2×18861881² = 711541109716322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18861181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9430940 + 9430941.

It is an arithmetic number, because the mean of its divisors is an integer number (9430941).

Almost surely, 2^18861881 is an apocalyptic number.

It is an amenable number.

18861881 is a deficient number, since it is larger than the sum of its proper divisors (1).

18861881 is an equidigital number, since it uses as much as digits as its factorization.

18861881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24576, while the sum is 41.

The square root of 18861881 is about 4343.0267095656. The cubic root of 18861881 is about 266.1920005619.

The spelling of 18861881 in words is "eighteen million, eight hundred sixty-one thousand, eight hundred eighty-one".