21111000122021 has 8 divisors (see below), whose sum is σ = 21839644060920. Its totient is φ = 20382401411008.

The previous prime is 21111000121949. The next prime is 21111000122083. The reversal of 21111000122021 is 12022100011112.

It can be written as a sum of positive squares in 4 ways, for example, as 11906026161121 + 9204973960900 = 3450511^2 + 3033970^2 .

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 21111000122021 - 2²² = 21110995927717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111000121987 and 21111000122005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111000122621) 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, 10355966 + ... + 12225711.

It is an arithmetic number, because the mean of its divisors is an integer number (2729955507615).

Almost surely, 2^{21111000122021} is an apocalyptic number.

It is an amenable number.

21111000122021 is a deficient number, since it is larger than the sum of its proper divisors (728643938899).

21111000122021 is a wasteful number, since it uses less digits than its factorization.

21111000122021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22613943.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21111000122021 its reverse (12022100011112), we get a palindrome (33133100133133).

The spelling of 21111000122021 in words is "twenty-one trillion, one hundred eleven billion, one hundred twenty-two thousand, twenty-one".