18038861 has 2 divisors, whose sum is σ = 18038862. Its totient is φ = 18038860.

The previous prime is 18038857. The next prime is 18038897. The reversal of 18038861 is 16883081.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14485636 + 3553225 = 3806^2 + 1885^2 .

It is a cyclic number.

It is not a de Polignac number, because 18038861 - 2² = 18038857 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18038821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9019430 + 9019431.

It is an arithmetic number, because the mean of its divisors is an integer number (9019431).

Almost surely, 2^18038861 is an apocalyptic number.

It is an amenable number.

18038861 is a deficient number, since it is larger than the sum of its proper divisors (1).

18038861 is an equidigital number, since it uses as much as digits as its factorization.

18038861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9216, while the sum is 35.

The square root of 18038861 is about 4247.2180306643. The cubic root of 18038861 is about 262.2626050261.

The spelling of 18038861 in words is "eighteen million, thirty-eight thousand, eight hundred sixty-one".