21238847 has 8 divisors (see below), whose sum is σ = 24308256. Its totient is φ = 18178272.

The previous prime is 21238843. The next prime is 21238859. The reversal of 21238847 is 74883212.

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

It is not a de Polignac number, because 21238847 - 2² = 21238843 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21238843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4193 + ... + 7749.

It is an arithmetic number, because the mean of its divisors is an integer number (3038532).

Almost surely, 2^21238847 is an apocalyptic number.

21238847 is a deficient number, since it is larger than the sum of its proper divisors (3069409).

21238847 is an equidigital number, since it uses as much as digits as its factorization.

21238847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4417.

The product of its digits is 21504, while the sum is 35.

The square root of 21238847 is about 4608.5623571782. The cubic root of 21238847 is about 276.9344464685.

The spelling of 21238847 in words is "twenty-one million, two hundred thirty-eight thousand, eight hundred forty-seven".