21102112211021 has 4 divisors (see below), whose sum is σ = 21189672842844. Its totient is φ = 21014551579200.

The previous prime is 21102112210987. The next prime is 21102112211023. The reversal of 21102112211021 is 12011221120112.

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 19273899942025 + 1828212268996 = 4390205^2 + 1352114^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21102112211021 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 (21102112211023) 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, 43780315550 + ... + 43780316031.

It is an arithmetic number, because the mean of its divisors is an integer number (5297418210711).

Almost surely, 2^{21102112211021} is an apocalyptic number.

It is an amenable number.

21102112211021 is a deficient number, since it is larger than the sum of its proper divisors (87560631823).

21102112211021 is an equidigital number, since it uses as much as digits as its factorization.

21102112211021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87560631822.

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

Adding to 21102112211021 its reverse (12011221120112), we get a palindrome (33113333331133).

The spelling of 21102112211021 in words is "twenty-one trillion, one hundred two billion, one hundred twelve million, two hundred eleven thousand, twenty-one".