21202110021121 has 8 divisors (see below), whose sum is σ = 21256301462760. Its totient is φ = 21147922528128.

The previous prime is 21202110021031. The next prime is 21202110021133. The reversal of 21202110021121 is 12112001120212.

It can be written as a sum of positive squares in 4 ways, for example, as 2375744409025 + 18826365612096 = 1541345^2 + 4338936^2 .

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 21202110021121 - 2²³ = 21202101632513 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21202110021095 and 21202110021104.

It is not an unprimeable number, because it can be changed into a prime (21202110021181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9919245 + ... + 11865733.

It is an arithmetic number, because the mean of its divisors is an integer number (2657037682845).

Almost surely, 2^{21202110021121} is an apocalyptic number.

It is an amenable number.

21202110021121 is a deficient number, since it is larger than the sum of its proper divisors (54191441639).

21202110021121 is a wasteful number, since it uses less digits than its factorization.

21202110021121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1974323.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21202110021121 its reverse (12112001120212), we get a palindrome (33314111141333).

The spelling of 21202110021121 in words is "twenty-one trillion, two hundred two billion, one hundred ten million, twenty-one thousand, one hundred twenty-one".