21036447 has 12 divisors (see below), whose sum is σ = 30428424. Its totient is φ = 14004720.

The previous prime is 21036443. The next prime is 21036451. The reversal of 21036447 is 74463012.

21036447 is a `hidden beast` number, since 2 + 10 + 3 + 644 + 7 = 666.

It is an interprime number because it is at equal distance from previous prime (21036443) and next prime (21036451).

It is not a de Polignac number, because 21036447 - 2² = 21036443 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21036447.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21036443) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8448 + ... + 10650.

It is an arithmetic number, because the mean of its divisors is an integer number (2535702).

Almost surely, 2^21036447 is an apocalyptic number.

21036447 is a deficient number, since it is larger than the sum of its proper divisors (9391977).

21036447 is a wasteful number, since it uses less digits than its factorization.

21036447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3270 (or 3267 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 21036447 is about 4586.5506647153. The cubic root of 21036447 is about 276.0519357211.

Adding to 21036447 its reverse (74463012), we get a palindrome (95499459).

The spelling of 21036447 in words is "twenty-one million, thirty-six thousand, four hundred forty-seven".