21121202121121 has 8 divisors (see below), whose sum is σ = 21164586261984. Its totient is φ = 21077819474880.

The previous prime is 21121202121073. The next prime is 21121202121241. The reversal of 21121202121121 is 12112120212112.

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 21121202121121 - 2²¹ = 21121200023969 is a prime.

It is a super-2 number, since 2×21121202121121² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121202121521) 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, 30540466 + ... + 31224388.

It is an arithmetic number, because the mean of its divisors is an integer number (2645573282748).

Almost surely, 2^{21121202121121} is an apocalyptic number.

It is an amenable number.

21121202121121 is a deficient number, since it is larger than the sum of its proper divisors (43384140863).

21121202121121 is an equidigital number, since it uses as much as digits as its factorization.

21121202121121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 747311.

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

Adding to 21121202121121 its reverse (12112120212112), we get a palindrome (33233322333233).

The spelling of 21121202121121 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred two million, one hundred twenty-one thousand, one hundred twenty-one".