21051227 has 4 divisors (see below), whose sum is σ = 21086856. Its totient is φ = 21015600.

The previous prime is 21051203. The next prime is 21051241. The reversal of 21051227 is 72215012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21051227 - 2¹⁰ = 21050203 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21051199 and 21051208.

It is not an unprimeable number, because it can be changed into a prime (21051257) 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 in 3 ways as a sum of consecutive naturals, for example, 16913 + ... + 18114.

It is an arithmetic number, because the mean of its divisors is an integer number (5271714).

Almost surely, 2^21051227 is an apocalyptic number.

21051227 is a deficient number, since it is larger than the sum of its proper divisors (35629).

21051227 is an equidigital number, since it uses as much as digits as its factorization.

21051227 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35628.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21051227 is about 4588.1616144160. The cubic root of 21051227 is about 276.1165710411.

Adding to 21051227 its reverse (72215012), we get a palindrome (93266239).

The spelling of 21051227 in words is "twenty-one million, fifty-one thousand, two hundred twenty-seven".