18582821 has 2 divisors, whose sum is σ = 18582822. Its totient is φ = 18582820.

The previous prime is 18582803. The next prime is 18582869. The reversal of 18582821 is 12828581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13912900 + 4669921 = 3730^2 + 2161^2 .

It is an emirp because it is prime and its reverse (12828581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18582821 - 2⁶ = 18582757 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18582871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9291410 + 9291411.

It is an arithmetic number, because the mean of its divisors is an integer number (9291411).

Almost surely, 2^18582821 is an apocalyptic number.

It is an amenable number.

18582821 is a deficient number, since it is larger than the sum of its proper divisors (1).

18582821 is an equidigital number, since it uses as much as digits as its factorization.

18582821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10240, while the sum is 35.

The square root of 18582821 is about 4310.7796278632. The cubic root of 18582821 is about 264.8727097227.

The spelling of 18582821 in words is "eighteen million, five hundred eighty-two thousand, eight hundred twenty-one".