21041281 has 8 divisors (see below), whose sum is σ = 21772800. Its totient is φ = 20313120.

The previous prime is 21041263. The next prime is 21041299. The reversal of 21041281 is 18214012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21041263) and next prime (21041299).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21041281 - 2⁵ = 21041249 is a prime.

It is a super-2 number, since 2×21041281² = 885471012241922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21041201) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24660 + ... + 25498.

It is an arithmetic number, because the mean of its divisors is an integer number (2721600).

Almost surely, 2^21041281 is an apocalyptic number.

It is an amenable number.

21041281 is a deficient number, since it is larger than the sum of its proper divisors (731519).

21041281 is an equidigital number, since it uses as much as digits as its factorization.

21041281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1679.

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 21041281 is about 4587.0776099822. The cubic root of 21041281 is about 276.0730789122.

Adding to 21041281 its reverse (18214012), we get a palindrome (39255293).

The spelling of 21041281 in words is "twenty-one million, forty-one thousand, two hundred eighty-one".