21002121102121 has 8 divisors (see below), whose sum is σ = 21220230081960. Its totient is φ = 20784044617728.

The previous prime is 21002121102119. The next prime is 21002121102167. The reversal of 21002121102121 is 12120112120012.

It can be written as a sum of positive squares in 4 ways, for example, as 297255034521 + 20704866067600 = 545211^2 + 4550260^2 .

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 21002121102121 - 2¹ = 21002121102119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002121102095 and 21002121102104.

It is not an unprimeable number, because it can be changed into a prime (21006121102121) 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, 6823456 + ... + 9410833.

It is an arithmetic number, because the mean of its divisors is an integer number (2652528760245).

Almost surely, 2^{21002121102121} is an apocalyptic number.

It is an amenable number.

21002121102121 is a deficient number, since it is larger than the sum of its proper divisors (218108979839).

21002121102121 is a wasteful number, since it uses less digits than its factorization.

21002121102121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16247723.

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

Adding to 21002121102121 its reverse (12120112120012), we get a palindrome (33122233222133).

The spelling of 21002121102121 in words is "twenty-one trillion, two billion, one hundred twenty-one million, one hundred two thousand, one hundred twenty-one".