2121200021021 has 4 divisors (see below), whose sum is σ = 2170530254112. Its totient is φ = 2071869787932.

The previous prime is 2121200020969. The next prime is 2121200021029. The reversal of 2121200021021 is 1201200021212.

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 de Polignac number, because none of the positive numbers 2^k-2121200021021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2121200020987 and 2121200021005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121200021029) 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, 24665116481 + ... + 24665116566.

It is an arithmetic number, because the mean of its divisors is an integer number (542632563528).

Almost surely, 2^{2121200021021} is an apocalyptic number.

It is an amenable number.

2121200021021 is a deficient number, since it is larger than the sum of its proper divisors (49330233091).

2121200021021 is an equidigital number, since it uses as much as digits as its factorization.

2121200021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49330233090.

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

Adding to 2121200021021 its reverse (1201200021212), we get a palindrome (3322400042233).

The spelling of 2121200021021 in words is "two trillion, one hundred twenty-one billion, two hundred million, twenty-one thousand, twenty-one".