21290441 has 2 divisors, whose sum is σ = 21290442. Its totient is φ = 21290440.

The previous prime is 21290419. The next prime is 21290447. The reversal of 21290441 is 14409212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11587216 + 9703225 = 3404^2 + 3115^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21290441 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21290447) 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, 10645220 + 10645221.

It is an arithmetic number, because the mean of its divisors is an integer number (10645221).

Almost surely, 2^21290441 is an apocalyptic number.

It is an amenable number.

21290441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21290441 is an equidigital number, since it uses as much as digits as its factorization.

21290441 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 21290441 is about 4614.1565859862. The cubic root of 21290441 is about 277.1585107612.

Adding to 21290441 its reverse (14409212), we get a palindrome (35699653).

The spelling of 21290441 in words is "twenty-one million, two hundred ninety thousand, four hundred forty-one".