21221183647 has 2 divisors, whose sum is σ = 21221183648. Its totient is φ = 21221183646.

The previous prime is 21221183617. The next prime is 21221183663. The reversal of 21221183647 is 74638112212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21221183647 - 2¹⁹ = 21220659359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221183617) 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 as a sum of consecutive naturals, namely, 10610591823 + 10610591824.

It is an arithmetic number, because the mean of its divisors is an integer number (10610591824).

Almost surely, 2^21221183647 is an apocalyptic number.

21221183647 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221183647 is an equidigital number, since it uses as much as digits as its factorization.

21221183647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 37.

Adding to 21221183647 its reverse (74638112212), we get a palindrome (95859295859).

The spelling of 21221183647 in words is "twenty-one billion, two hundred twenty-one million, one hundred eighty-three thousand, six hundred forty-seven".