21035281 has 2 divisors, whose sum is σ = 21035282. Its totient is φ = 21035280.

The previous prime is 21035269. The next prime is 21035297. The reversal of 21035281 is 18253012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12362256 + 8673025 = 3516^2 + 2945^2 .

It is a cyclic number.

It is not a de Polignac number, because 21035281 - 2⁵ = 21035249 is a prime.

It is a super-2 number, since 2×21035281² = 884966093497922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21035981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10517640 + 10517641.

It is an arithmetic number, because the mean of its divisors is an integer number (10517641).

Almost surely, 2^21035281 is an apocalyptic number.

It is an amenable number.

21035281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21035281 is an equidigital number, since it uses as much as digits as its factorization.

21035281 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 21035281 is about 4586.4235521809. The cubic root of 21035281 is about 276.0468353271.

Adding to 21035281 its reverse (18253012), we get a palindrome (39288293).

It can be divided in two parts, 21035 and 281, that added together give a square (21316 = 146²).

The spelling of 21035281 in words is "twenty-one million, thirty-five thousand, two hundred eighty-one".