18871841 has 2 divisors, whose sum is σ = 18871842. Its totient is φ = 18871840.

The previous prime is 18871789. The next prime is 18871859. The reversal of 18871841 is 14817881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11424400 + 7447441 = 3380^2 + 2729^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18871841 is a prime.

It is a super-2 number, since 2×18871841² = 712292765458562, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18871795 and 18871804.

It is not a weakly prime, because it can be changed into another prime (18871861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9435920 + 9435921.

It is an arithmetic number, because the mean of its divisors is an integer number (9435921).

Almost surely, 2^18871841 is an apocalyptic number.

It is an amenable number.

18871841 is a deficient number, since it is larger than the sum of its proper divisors (1).

18871841 is an equidigital number, since it uses as much as digits as its factorization.

18871841 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14336, while the sum is 38.

The square root of 18871841 is about 4344.1732239864. The cubic root of 18871841 is about 266.2388464694.

The spelling of 18871841 in words is "eighteen million, eight hundred seventy-one thousand, eight hundred forty-one".