18374821 has 2 divisors, whose sum is σ = 18374822. Its totient is φ = 18374820.

The previous prime is 18374771. The next prime is 18374831. The reversal of 18374821 is 12847381.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17313921 + 1060900 = 4161^2 + 1030^2 .

It is an emirp because it is prime and its reverse (12847381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18374821 - 2¹³ = 18366629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18374831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9187410 + 9187411.

It is an arithmetic number, because the mean of its divisors is an integer number (9187411).

Almost surely, 2^18374821 is an apocalyptic number.

It is an amenable number.

18374821 is a deficient number, since it is larger than the sum of its proper divisors (1).

18374821 is an equidigital number, since it uses as much as digits as its factorization.

18374821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10752, while the sum is 34.

The square root of 18374821 is about 4286.5861708357. The cubic root of 18374821 is about 263.8807475252.

The spelling of 18374821 in words is "eighteen million, three hundred seventy-four thousand, eight hundred twenty-one".