20111021001221 has 4 divisors (see below), whose sum is σ = 20111083874700. Its totient is φ = 20110958127744.

The previous prime is 20111021001209. The next prime is 20111021001223. The reversal of 20111021001221 is 12210012011102.

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 2398378768900 + 17712642232321 = 1548670^2 + 4208639^2 .

It is a cyclic number.

It is not a de Polignac number, because 20111021001221 - 2¹⁸ = 20111020739077 is a prime.

It is a super-2 number, since 2×20111021001221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20111021001196 and 20111021001205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20111021001223) 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, 30954476 + ... + 31597493.

It is an arithmetic number, because the mean of its divisors is an integer number (5027770968675).

Almost surely, 2^{20111021001221} is an apocalyptic number.

It is an amenable number.

20111021001221 is a deficient number, since it is larger than the sum of its proper divisors (62873479).

20111021001221 is an equidigital number, since it uses as much as digits as its factorization.

20111021001221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62873478.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 20111021001221 its reverse (12210012011102), we get a palindrome (32321033012323).

The spelling of 20111021001221 in words is "twenty trillion, one hundred eleven billion, twenty-one million, one thousand, two hundred twenty-one".