21247227 has 24 divisors (see below), whose sum is σ = 32048640. Its totient is φ = 13547520.

The previous prime is 21247211. The next prime is 21247231. The reversal of 21247227 is 72274212.

It is not a de Polignac number, because 21247227 - 2⁴ = 21247211 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21247227.

It is not an unprimeable number, because it can be changed into a prime (21247207) 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 23 ways as a sum of consecutive naturals, for example, 32827 + ... + 33467.

It is an arithmetic number, because the mean of its divisors is an integer number (1335360).

Almost surely, 2^21247227 is an apocalyptic number.

21247227 is a deficient number, since it is larger than the sum of its proper divisors (10801413).

21247227 is a wasteful number, since it uses less digits than its factorization.

21247227 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 803 (or 800 counting only the distinct ones).

The product of its digits is 3136, while the sum is 27.

The square root of 21247227 is about 4609.4714447537. The cubic root of 21247227 is about 276.9708641000.

The spelling of 21247227 in words is "twenty-one million, two hundred forty-seven thousand, two hundred twenty-seven".