21021121012121 has 16 divisors (see below), whose sum is σ = 21997162635264. Its totient is φ = 20066567586624.

The previous prime is 21021121012037. The next prime is 21021121012123. The reversal of 21021121012121 is 12121012112012.

It is a cyclic number.

It is not a de Polignac number, because 21021121012121 - 2³⁴ = 21003941142937 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21021121012121.

It is not an unprimeable number, because it can be changed into a prime (21021121012123) 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 15 ways as a sum of consecutive naturals, for example, 93511760 + ... + 93736286.

It is an arithmetic number, because the mean of its divisors is an integer number (1374822664704).

Almost surely, 2^{21021121012121} is an apocalyptic number.

It is an amenable number.

21021121012121 is a deficient number, since it is larger than the sum of its proper divisors (976041623143).

21021121012121 is a wasteful number, since it uses less digits than its factorization.

21021121012121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272360.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21021121012121 its reverse (12121012112012), we get a palindrome (33142133124133).

The spelling of 21021121012121 in words is "twenty-one trillion, twenty-one billion, one hundred twenty-one million, twelve thousand, one hundred twenty-one".