18218477 has 2 divisors, whose sum is σ = 18218478. Its totient is φ = 18218476.

The previous prime is 18218449. The next prime is 18218479. The reversal of 18218477 is 77481281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10118761 + 8099716 = 3181^2 + 2846^2 .

It is an emirp because it is prime and its reverse (77481281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18218477 - 2⁶ = 18218413 is a prime.

Together with 18218479, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18218477.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18218479) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9109238 + 9109239.

It is an arithmetic number, because the mean of its divisors is an integer number (9109239).

Almost surely, 2^18218477 is an apocalyptic number.

It is an amenable number.

18218477 is a deficient number, since it is larger than the sum of its proper divisors (1).

18218477 is an equidigital number, since it uses as much as digits as its factorization.

18218477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25088, while the sum is 38.

The square root of 18218477 is about 4268.3107899964. The cubic root of 18218477 is about 263.1301962026.

The spelling of 18218477 in words is "eighteen million, two hundred eighteen thousand, four hundred seventy-seven".