21121022112121 has 4 divisors (see below), whose sum is σ = 21612208672912. Its totient is φ = 20629835551332.

The previous prime is 21121022112049. The next prime is 21121022112137. The reversal of 21121022112121 is 12121122012112.

It is a happy number.

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 not a de Polignac number, because 21121022112121 - 2³¹ = 21118874628473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121022112161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245593280331 + ... + 245593280416.

It is an arithmetic number, because the mean of its divisors is an integer number (5403052168228).

Almost surely, 2^{21121022112121} is an apocalyptic number.

It is an amenable number.

21121022112121 is a deficient number, since it is larger than the sum of its proper divisors (491186560791).

21121022112121 is an equidigital number, since it uses as much as digits as its factorization.

21121022112121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491186560790.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21121022112121 its reverse (12121122012112), we get a palindrome (33242144124233).

The spelling of 21121022112121 in words is "twenty-one trillion, one hundred twenty-one billion, twenty-two million, one hundred twelve thousand, one hundred twenty-one".