2112121210021 has 4 divisors (see below), whose sum is σ = 2135852909100. Its totient is φ = 2088389510944.

The previous prime is 2112121210007. The next prime is 2112121210081. The reversal of 2112121210021 is 1200121212112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 758414556900 + 1353706653121 = 870870^2 + 1163489^2 .

It is a cyclic number.

It is not a de Polignac number, because 2112121210021 - 2⁹ = 2112121209509 is a prime.

It is a super-2 number, since 2×2112121210021² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2112121209977 and 2112121210004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2112121210081) 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 3 ways as a sum of consecutive naturals, for example, 11865849406 + ... + 11865849583.

It is an arithmetic number, because the mean of its divisors is an integer number (533963227275).

Almost surely, 2^{2112121210021} is an apocalyptic number.

It is an amenable number.

2112121210021 is a deficient number, since it is larger than the sum of its proper divisors (23731699079).

2112121210021 is an equidigital number, since it uses as much as digits as its factorization.

2112121210021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23731699078.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 2112121210021 its reverse (1200121212112), we get a palindrome (3312242422133).

The spelling of 2112121210021 in words is "two trillion, one hundred twelve billion, one hundred twenty-one million, two hundred ten thousand, twenty-one".