21112120202021 has 4 divisors (see below), whose sum is σ = 22223284423200. Its totient is φ = 20000955980844.

The previous prime is 21112120201891. The next prime is 21112120202029. The reversal of 21112120202021 is 12020202121112.

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 a de Polignac number, because none of the positive numbers 2^k-21112120202021 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 (21112120202029) 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, 555582110561 + ... + 555582110598.

It is an arithmetic number, because the mean of its divisors is an integer number (5555821105800).

Almost surely, 2^{21112120202021} is an apocalyptic number.

It is an amenable number.

21112120202021 is a deficient number, since it is larger than the sum of its proper divisors (1111164221179).

21112120202021 is a wasteful number, since it uses less digits than its factorization.

21112120202021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1111164221178.

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

Adding to 21112120202021 its reverse (12020202121112), we get a palindrome (33132322323133).

The spelling of 21112120202021 in words is "twenty-one trillion, one hundred twelve billion, one hundred twenty million, two hundred two thousand, twenty-one".