18051989 has 2 divisors, whose sum is σ = 18051990. Its totient is φ = 18051988.

The previous prime is 18051973. The next prime is 18051997. The reversal of 18051989 is 98915081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12567025 + 5484964 = 3545^2 + 2342^2 .

It is a cyclic number.

It is not a de Polignac number, because 18051989 - 2⁴ = 18051973 is a prime.

It is a super-2 number, since 2×18051989² = 651748613712242, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18051289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9025994 + 9025995.

It is an arithmetic number, because the mean of its divisors is an integer number (9025995).

Almost surely, 2^18051989 is an apocalyptic number.

It is an amenable number.

18051989 is a deficient number, since it is larger than the sum of its proper divisors (1).

18051989 is an equidigital number, since it uses as much as digits as its factorization.

18051989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 41.

The square root of 18051989 is about 4248.7632318123. The cubic root of 18051989 is about 262.3262111963.

The spelling of 18051989 in words is "eighteen million, fifty-one thousand, nine hundred eighty-nine".