18438437 has 2 divisors, whose sum is σ = 18438438. Its totient is φ = 18438436.

The previous prime is 18438391. The next prime is 18438457. The reversal of 18438437 is 73483481.

It is a Cunningham number, because it is equal to 4294²+1.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18438436 + 1 = 4294^2 + 1^2 .

It is an emirp because it is prime and its reverse (73483481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18438437 - 2⁶ = 18438373 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18438437.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18438457) 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, 9219218 + 9219219.

It is an arithmetic number, because the mean of its divisors is an integer number (9219219).

Almost surely, 2^18438437 is an apocalyptic number.

It is an amenable number.

18438437 is a deficient number, since it is larger than the sum of its proper divisors (1).

18438437 is an equidigital number, since it uses as much as digits as its factorization.

18438437 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64512, while the sum is 38.

The square root of 18438437 is about 4294.0001164415. Note that the first 3 decimals coincide. The cubic root of 18438437 is about 264.1849264856.

The spelling of 18438437 in words is "eighteen million, four hundred thirty-eight thousand, four hundred thirty-seven".