21012221020121 has 8 divisors (see below), whose sum is σ = 21459599304960. Its totient is φ = 20564855641728.

The previous prime is 21012221020073. The next prime is 21012221020127. The reversal of 21012221020121 is 12102012221012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012221020121 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21012221020121.

It is not an unprimeable number, because it can be changed into a prime (21012221020127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 100265 + ... + 6483401.

It is an arithmetic number, because the mean of its divisors is an integer number (2682449913120).

Almost surely, 2^{21012221020121} is an apocalyptic number.

It is an amenable number.

21012221020121 is a deficient number, since it is larger than the sum of its proper divisors (447378284839).

21012221020121 is an equidigital number, since it uses as much as digits as its factorization.

21012221020121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6453223.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21012221020121 its reverse (12102012221012), we get a palindrome (33114233241133).

The spelling of 21012221020121 in words is "twenty-one trillion, twelve billion, two hundred twenty-one million, twenty thousand, one hundred twenty-one".