2121211220021 has 8 divisors (see below), whose sum is σ = 2159938351200. Its totient is φ = 2082797669232.

The previous prime is 2121211220003. The next prime is 2121211220041. The reversal of 2121211220021 is 1200221121212.

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-2121211220021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121211220041) 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, 78381446 + ... + 78408503.

It is an arithmetic number, because the mean of its divisors is an integer number (269992293900).

Almost surely, 2^{2121211220021} is an apocalyptic number.

It is an amenable number.

2121211220021 is a deficient number, since it is larger than the sum of its proper divisors (38727131179).

2121211220021 is a wasteful number, since it uses less digits than its factorization.

2121211220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156790195.

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

Adding to 2121211220021 its reverse (1200221121212), we get a palindrome (3321432341233).

The spelling of 2121211220021 in words is "two trillion, one hundred twenty-one billion, two hundred eleven million, two hundred twenty thousand, twenty-one".