21121002021121 has 8 divisors (see below), whose sum is σ = 21246328343520. Its totient is φ = 20995757164608.

The previous prime is 21121002021107. The next prime is 21121002021151. The reversal of 21121002021121 is 12112020012112.

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 21121002021121 - 2¹⁷ = 21121001890049 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121002021095 and 21121002021104.

It is not an unprimeable number, because it can be changed into a prime (21121002021151) 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, 19846371 + ... + 20883496.

It is an arithmetic number, because the mean of its divisors is an integer number (2655791042940).

Almost surely, 2^{21121002021121} is an apocalyptic number.

It is an amenable number.

21121002021121 is a deficient number, since it is larger than the sum of its proper divisors (125326322399).

21121002021121 is a wasteful number, since it uses less digits than its factorization.

21121002021121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40732943.

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

Adding to 21121002021121 its reverse (12112020012112), we get a palindrome (33233022033233).

The spelling of 21121002021121 in words is "twenty-one trillion, one hundred twenty-one billion, two million, twenty-one thousand, one hundred twenty-one".