18622921 has 2 divisors, whose sum is σ = 18622922. Its totient is φ = 18622920.

The previous prime is 18622883. The next prime is 18622943. The reversal of 18622921 is 12922681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11526025 + 7096896 = 3395^2 + 2664^2 .

It is an emirp because it is prime and its reverse (12922681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18622921 - 2¹¹ = 18620873 is a prime.

It is not a weakly prime, because it can be changed into another prime (18622421) 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, 9311460 + 9311461.

It is an arithmetic number, because the mean of its divisors is an integer number (9311461).

Almost surely, 2^18622921 is an apocalyptic number.

It is an amenable number.

18622921 is a deficient number, since it is larger than the sum of its proper divisors (1).

18622921 is an equidigital number, since it uses as much as digits as its factorization.

18622921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 31.

The square root of 18622921 is about 4315.4282522132. The cubic root of 18622921 is about 265.0630964031.

The spelling of 18622921 in words is "eighteen million, six hundred twenty-two thousand, nine hundred twenty-one".