21161443 has 2 divisors, whose sum is σ = 21161444. Its totient is φ = 21161442.

The previous prime is 21161417. The next prime is 21161467. The reversal of 21161443 is 34416112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21161443 is a prime.

It is not a weakly prime, because it can be changed into another prime (21561443) 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, 10580721 + 10580722.

It is an arithmetic number, because the mean of its divisors is an integer number (10580722).

Almost surely, 2^21161443 is an apocalyptic number.

21161443 is a deficient number, since it is larger than the sum of its proper divisors (1).

21161443 is an equidigital number, since it uses as much as digits as its factorization.

21161443 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 22.

The square root of 21161443 is about 4600.1568451521. The cubic root of 21161443 is about 276.5976119975.

Adding to 21161443 its reverse (34416112), we get a palindrome (55577555).

The spelling of 21161443 in words is "twenty-one million, one hundred sixty-one thousand, four hundred forty-three".