18893821 has 2 divisors, whose sum is σ = 18893822. Its totient is φ = 18893820.

The previous prime is 18893801. The next prime is 18893837. The reversal of 18893821 is 12839881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14546596 + 4347225 = 3814^2 + 2085^2 .

It is a cyclic number.

It is not a de Polignac number, because 18893821 - 2⁵ = 18893789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18893801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9446910 + 9446911.

It is an arithmetic number, because the mean of its divisors is an integer number (9446911).

Almost surely, 2^18893821 is an apocalyptic number.

It is an amenable number.

18893821 is a deficient number, since it is larger than the sum of its proper divisors (1).

18893821 is an equidigital number, since it uses as much as digits as its factorization.

18893821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 40.

The square root of 18893821 is about 4346.7023132485. The cubic root of 18893821 is about 266.3421690052.

The spelling of 18893821 in words is "eighteen million, eight hundred ninety-three thousand, eight hundred twenty-one".