12890821 has 2 divisors, whose sum is σ = 12890822. Its totient is φ = 12890820.

The previous prime is 12890809. The next prime is 12890861. The reversal of 12890821 is 12809821.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9541921 + 3348900 = 3089^2 + 1830^2 .

It is a cyclic number.

It is not a de Polignac number, because 12890821 - 2⁵ = 12890789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12890861) 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, 6445410 + 6445411.

It is an arithmetic number, because the mean of its divisors is an integer number (6445411).

Almost surely, 2^12890821 is an apocalyptic number.

It is an amenable number.

12890821 is a deficient number, since it is larger than the sum of its proper divisors (1).

12890821 is an equidigital number, since it uses as much as digits as its factorization.

12890821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 12890821 is about 3590.3789493590. The cubic root of 12890821 is about 234.4733702862.

The spelling of 12890821 in words is "twelve million, eight hundred ninety thousand, eight hundred twenty-one".