18091939 has 2 divisors, whose sum is σ = 18091940. Its totient is φ = 18091938.

The previous prime is 18091919. The next prime is 18091963. The reversal of 18091939 is 93919081.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18091939 - 2²¹ = 15994787 is a prime.

It is not a weakly prime, because it can be changed into another prime (18091919) 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, 9045969 + 9045970.

It is an arithmetic number, because the mean of its divisors is an integer number (9045970).

Almost surely, 2^18091939 is an apocalyptic number.

18091939 is a deficient number, since it is larger than the sum of its proper divisors (1).

18091939 is an equidigital number, since it uses as much as digits as its factorization.

18091939 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496, while the sum is 40.

The square root of 18091939 is about 4253.4620017111. The cubic root of 18091939 is about 262.5195825149.

The spelling of 18091939 in words is "eighteen million, ninety-one thousand, nine hundred thirty-nine".