21002000121121 has 4 divisors (see below), whose sum is σ = 21267848224000. Its totient is φ = 20736152018244.

The previous prime is 21002000121107. The next prime is 21002000121131. The reversal of 21002000121121 is 12112100020012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21002000121121 - 2⁹ = 21002000120609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002000121131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132924051321 + ... + 132924051478.

It is an arithmetic number, because the mean of its divisors is an integer number (5316962056000).

Almost surely, 2^{21002000121121} is an apocalyptic number.

It is an amenable number.

21002000121121 is a deficient number, since it is larger than the sum of its proper divisors (265848102879).

21002000121121 is an equidigital number, since it uses as much as digits as its factorization.

21002000121121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265848102878.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21002000121121 its reverse (12112100020012), we get a palindrome (33114100141133).

The spelling of 21002000121121 in words is "twenty-one trillion, two billion, one hundred twenty-one thousand, one hundred twenty-one".