21221545224656 has 80 divisors (see below), whose sum is σ = 48414924246528. Its totient is φ = 8821829913600.

The previous prime is 21221545224647. The next prime is 21221545224667. The reversal of 21221545224656 is 65642254512212.

It is a self number, because there is not a number n which added to its sum of digits gives 21221545224656.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12562280 + ... + 14151111.

Almost surely, 2^{21221545224656} is an apocalyptic number.

It is an amenable number.

21221545224656 is an abundant number, since it is smaller than the sum of its proper divisors (27193379021872).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21221545224656 is a wasteful number, since it uses less digits than its factorization.

21221545224656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26713620 (or 26713614 counting only the distinct ones).

The product of its digits is 2304000, while the sum is 47.

Adding to 21221545224656 its reverse (65642254512212), we get a palindrome (86863799736868).

The spelling of 21221545224656 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred forty-five million, two hundred twenty-four thousand, six hundred fifty-six".