21011021122121 has 16 divisors (see below), whose sum is σ = 21734816376000. Its totient is φ = 20295441995328.

The previous prime is 21011021122111. The next prime is 21011021122123. The reversal of 21011021122121 is 12122112011012.

It is a cyclic number.

It is not a de Polignac number, because 21011021122121 - 2⁶ = 21011021122057 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 21011021122121.

It is not an unprimeable number, because it can be changed into a prime (21011021122123) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 287986955 + ... + 288059903.

It is an arithmetic number, because the mean of its divisors is an integer number (1358426023500).

Almost surely, 2^{21011021122121} is an apocalyptic number.

It is an amenable number.

21011021122121 is a deficient number, since it is larger than the sum of its proper divisors (723795253879).

21011021122121 is a wasteful number, since it uses less digits than its factorization.

21011021122121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129128.

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

Adding to 21011021122121 its reverse (12122112011012), we get a palindrome (33133133133133).

It can be divided in two parts, 2101102 and 1122121, that added together give a palindrome (3223223).

The spelling of 21011021122121 in words is "twenty-one trillion, eleven billion, twenty-one million, one hundred twenty-two thousand, one hundred twenty-one".