18538643 has 2 divisors, whose sum is σ = 18538644. Its totient is φ = 18538642.

The previous prime is 18538613. The next prime is 18538679. The reversal of 18538643 is 34683581.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18538643 - 2⁶ = 18538579 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18538597 and 18538606.

It is not a weakly prime, because it can be changed into another prime (18538613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9269321 + 9269322.

It is an arithmetic number, because the mean of its divisors is an integer number (9269322).

Almost surely, 2^18538643 is an apocalyptic number.

18538643 is a deficient number, since it is larger than the sum of its proper divisors (1).

18538643 is an equidigital number, since it uses as much as digits as its factorization.

18538643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69120, while the sum is 38.

The square root of 18538643 is about 4305.6524476553. The cubic root of 18538643 is about 264.6626441689.

The spelling of 18538643 in words is "eighteen million, five hundred thirty-eight thousand, six hundred forty-three".