21227847 has 4 divisors (see below), whose sum is σ = 28303800. Its totient is φ = 14151896.

The previous prime is 21227821. The next prime is 21227851. The reversal of 21227847 is 74872212.

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 21227847 - 2⁶ = 21227783 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21227867) 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, 3537972 + ... + 3537977.

It is an arithmetic number, because the mean of its divisors is an integer number (7075950).

Almost surely, 2^21227847 is an apocalyptic number.

21227847 is a deficient number, since it is larger than the sum of its proper divisors (7075953).

21227847 is an equidigital number, since it uses as much as digits as its factorization.

21227847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7075952.

The product of its digits is 12544, while the sum is 33.

The square root of 21227847 is about 4607.3687718697. The cubic root of 21227847 is about 276.8866283522.

The spelling of 21227847 in words is "twenty-one million, two hundred twenty-seven thousand, eight hundred forty-seven".