21122121112021 has 8 divisors (see below), whose sum is σ = 22045807105920. Its totient is φ = 20198879526672.

The previous prime is 21122121111967. The next prime is 21122121112051. The reversal of 21122121112021 is 12021112122112.

It is a happy number.

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 21122121112021 - 2⁷ = 21122121111893 is a prime.

It is a super-2 number, since 2×21122121112021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21122121112021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122121112051) 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, 111005001 + ... + 111195118.

It is an arithmetic number, because the mean of its divisors is an integer number (2755725888240).

Almost surely, 2^{21122121112021} is an apocalyptic number.

It is an amenable number.

21122121112021 is a deficient number, since it is larger than the sum of its proper divisors (923685993899).

21122121112021 is a wasteful number, since it uses less digits than its factorization.

21122121112021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222204275.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21122121112021 its reverse (12021112122112), we get a palindrome (33143233234133).

The spelling of 21122121112021 in words is "twenty-one trillion, one hundred twenty-two billion, one hundred twenty-one million, one hundred twelve thousand, twenty-one".