21741281 has 2 divisors, whose sum is σ = 21741282. Its totient is φ = 21741280.

The previous prime is 21741277. The next prime is 21741287. The reversal of 21741281 is 18214712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20566225 + 1175056 = 4535^2 + 1084^2 .

It is a cyclic number.

It is not a de Polignac number, because 21741281 - 2² = 21741277 is a prime.

It is a super-2 number, since 2×21741281² = 945366599041922, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21741281.

It is not a weakly prime, because it can be changed into another prime (21741287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10870640 + 10870641.

It is an arithmetic number, because the mean of its divisors is an integer number (10870641).

Almost surely, 2^21741281 is an apocalyptic number.

It is an amenable number.

21741281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21741281 is an equidigital number, since it uses as much as digits as its factorization.

21741281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 896, while the sum is 26.

The square root of 21741281 is about 4662.7546579249. The cubic root of 21741281 is about 279.1012038481.

Adding to 21741281 its reverse (18214712), we get a palindrome (39955993).

It can be divided in two parts, 21741 and 281, that added together give a palindrome (22022).

The spelling of 21741281 in words is "twenty-one million, seven hundred forty-one thousand, two hundred eighty-one".