21459281 has 2 divisors, whose sum is σ = 21459282. Its totient is φ = 21459280.

The previous prime is 21459259. The next prime is 21459301. The reversal of 21459281 is 18295412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12845056 + 8614225 = 3584^2 + 2935^2 .

It is a cyclic number.

It is not a de Polignac number, because 21459281 - 2¹⁰ = 21458257 is a prime.

It is a super-2 number, since 2×21459281² = 921001482073922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21459211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10729640 + 10729641.

It is an arithmetic number, because the mean of its divisors is an integer number (10729641).

Almost surely, 2^21459281 is an apocalyptic number.

It is an amenable number.

21459281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21459281 is an equidigital number, since it uses as much as digits as its factorization.

21459281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 32.

The square root of 21459281 is about 4632.4163241229. The cubic root of 21459281 is about 277.8892343779.

It can be divided in two parts, 214 and 59281, that added together give a palindrome (59495).

The spelling of 21459281 in words is "twenty-one million, four hundred fifty-nine thousand, two hundred eighty-one".