21224220521 has 8 divisors (see below), whose sum is σ = 24257823360. Its totient is φ = 18191010528.

The previous prime is 21224220499. The next prime is 21224220527. The reversal of 21224220521 is 12502242212.

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

It is a cyclic number.

It is not a de Polignac number, because 21224220521 - 2¹⁴ = 21224204137 is a prime.

It is a super-2 number, since 2×21224220521² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21224220527) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28460 + ... + 207986.

It is an arithmetic number, because the mean of its divisors is an integer number (3032227920).

Almost surely, 2^21224220521 is an apocalyptic number.

It is an amenable number.

21224220521 is a deficient number, since it is larger than the sum of its proper divisors (3033602839).

21224220521 is a wasteful number, since it uses less digits than its factorization.

21224220521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196423.

The product of its (nonzero) digits is 1280, while the sum is 23.

Adding to 21224220521 its reverse (12502242212), we get a palindrome (33726462733).

The spelling of 21224220521 in words is "twenty-one billion, two hundred twenty-four million, two hundred twenty thousand, five hundred twenty-one".