18866641 has 2 divisors, whose sum is σ = 18866642. Its totient is φ = 18866640.

The previous prime is 18866587. The next prime is 18866657. The reversal of 18866641 is 14666881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18524416 + 342225 = 4304^2 + 585^2 .

It is a cyclic number.

It is not a de Polignac number, because 18866641 - 2¹⁷ = 18735569 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18866594 and 18866603.

It is not a weakly prime, because it can be changed into another prime (18866671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9433320 + 9433321.

It is an arithmetic number, because the mean of its divisors is an integer number (9433321).

Almost surely, 2^18866641 is an apocalyptic number.

It is an amenable number.

18866641 is a deficient number, since it is larger than the sum of its proper divisors (1).

18866641 is an equidigital number, since it uses as much as digits as its factorization.

18866641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55296, while the sum is 40.

The square root of 18866641 is about 4343.5746799152. The cubic root of 18866641 is about 266.2143908235.

The spelling of 18866641 in words is "eighteen million, eight hundred sixty-six thousand, six hundred forty-one".