18244991 has 2 divisors, whose sum is σ = 18244992. Its totient is φ = 18244990.

The previous prime is 18244987. The next prime is 18244999. The reversal of 18244991 is 19944281.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18244991 - 2² = 18244987 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 (18244999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9122495 + 9122496.

It is an arithmetic number, because the mean of its divisors is an integer number (9122496).

Almost surely, 2^18244991 is an apocalyptic number.

18244991 is a deficient number, since it is larger than the sum of its proper divisors (1).

18244991 is an equidigital number, since it uses as much as digits as its factorization.

18244991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 38.

The square root of 18244991 is about 4271.4155733199. The cubic root of 18244991 is about 263.2577819188.

The spelling of 18244991 in words is "eighteen million, two hundred forty-four thousand, nine hundred ninety-one".