21344247 has 12 divisors (see below), whose sum is σ = 31178160. Its totient is φ = 14069088.

The previous prime is 21344243. The next prime is 21344249. The reversal of 21344247 is 74244312.

21344247 is a `hidden beast` number, since 213 + 442 + 4 + 7 = 666.

It is not a de Polignac number, because 21344247 - 2² = 21344243 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21344247.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21344243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12523 + ... + 14124.

It is an arithmetic number, because the mean of its divisors is an integer number (2598180).

Almost surely, 2^21344247 is an apocalyptic number.

21344247 is a deficient number, since it is larger than the sum of its proper divisors (9833913).

21344247 is a wasteful number, since it uses less digits than its factorization.

21344247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26742 (or 26739 counting only the distinct ones).

The product of its digits is 5376, while the sum is 27.

The square root of 21344247 is about 4619.9834415288. The cubic root of 21344247 is about 277.3917961390.

Adding to 21344247 its reverse (74244312), we get a palindrome (95588559).

The spelling of 21344247 in words is "twenty-one million, three hundred forty-four thousand, two hundred forty-seven".