20111000001221 has 4 divisors (see below), whose sum is σ = 20578697675712. Its totient is φ = 19643302326732.

The previous prime is 20111000001199. The next prime is 20111000001247. The reversal of 20111000001221 is 12210000011102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20111000001221 is a prime.

It is a super-2 number, since 2×20111000001221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20111000003221) 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, 233848837181 + ... + 233848837266.

It is an arithmetic number, because the mean of its divisors is an integer number (5144674418928).

Almost surely, 2^{20111000001221} is an apocalyptic number.

It is an amenable number.

20111000001221 is a deficient number, since it is larger than the sum of its proper divisors (467697674491).

20111000001221 is an equidigital number, since it uses as much as digits as its factorization.

20111000001221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467697674490.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 20111000001221 its reverse (12210000011102), we get a palindrome (32321000012323).

The spelling of 20111000001221 in words is "twenty trillion, one hundred eleven billion, one thousand, two hundred twenty-one".