21112120101221 has 8 divisors (see below), whose sum is σ = 21338509191384. Its totient is φ = 20885909345280.

The previous prime is 21112120101203. The next prime is 21112120101227. The reversal of 21112120101221 is 12210102121112.

It can be written as a sum of positive squares in 4 ways, for example, as 946281472900 + 20165838628321 = 972770^2 + 4490639^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21112120101221 - 2¹⁴ = 21112120084837 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 21112120101221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112120101227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44345510 + ... + 44819063.

It is an arithmetic number, because the mean of its divisors is an integer number (2667313648923).

Almost surely, 2^{21112120101221} is an apocalyptic number.

It is an amenable number.

21112120101221 is a deficient number, since it is larger than the sum of its proper divisors (226389090163).

21112120101221 is an equidigital number, since it uses as much as digits as its factorization.

21112120101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89167111.

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

Adding to 21112120101221 its reverse (12210102121112), we get a palindrome (33322222222333).

The spelling of 21112120101221 in words is "twenty-one trillion, one hundred twelve billion, one hundred twenty million, one hundred one thousand, two hundred twenty-one".