20021000212121 has 8 divisors (see below), whose sum is σ = 20133074281320. Its totient is φ = 19909149622272.

The previous prime is 20021000212079. The next prime is 20021000212123. The reversal of 20021000212121 is 12121200012002.

It can be written as a sum of positive squares in 4 ways, for example, as 925944307600 + 19095055904521 = 962260^2 + 4369789^2 .

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-20021000212121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021000212096 and 20021000212105.

It is not an unprimeable number, because it can be changed into a prime (20021000212123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55690160 + ... + 56048513.

It is an arithmetic number, because the mean of its divisors is an integer number (2516634285165).

Almost surely, 2^{20021000212121} is an apocalyptic number.

It is an amenable number.

20021000212121 is a deficient number, since it is larger than the sum of its proper divisors (112074069199).

20021000212121 is a wasteful number, since it uses less digits than its factorization.

20021000212121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111739675.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 20021000212121 its reverse (12121200012002), we get a palindrome (32142200224123).

The spelling of 20021000212121 in words is "twenty trillion, twenty-one billion, two hundred twelve thousand, one hundred twenty-one".