21616221344221 has 32 divisors (see below), whose sum is σ = 26336014935552. Its totient is φ = 17319423283200.

The previous prime is 21616221344143. The next prime is 21616221344231. The reversal of 21616221344221 is 12244312261612.

It is a cyclic number.

It is not a de Polignac number, because 21616221344221 - 2²¹ = 21616219247069 is a prime.

It is a super-2 number, since 2×21616221344221² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21616221344231) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23414635 + ... + 24320311.

It is an arithmetic number, because the mean of its divisors is an integer number (823000466736).

Almost surely, 2^{21616221344221} is an apocalyptic number.

It is an amenable number.

21616221344221 is a deficient number, since it is larger than the sum of its proper divisors (4719793591331).

21616221344221 is a wasteful number, since it uses less digits than its factorization.

21616221344221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 907069.

The product of its digits is 55296, while the sum is 37.

The spelling of 21616221344221 in words is "twenty-one trillion, six hundred sixteen billion, two hundred twenty-one million, three hundred forty-four thousand, two hundred twenty-one".