1211111000221 has 4 divisors (see below), whose sum is σ = 1211246738272. Its totient is φ = 1210975262172.

The previous prime is 1211111000173. The next prime is 1211111000227. The reversal of 1211111000221 is 1220001111121.

It is a happy number.

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-1211111000221 is a prime.

It is a super-2 number, since 2×1211111000221² (a number of 25 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 (1211111000227) 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, 67855641 + ... + 67873486.

It is an arithmetic number, because the mean of its divisors is an integer number (302811684568).

Almost surely, 2^{1211111000221} is an apocalyptic number.

It is an amenable number.

1211111000221 is a deficient number, since it is larger than the sum of its proper divisors (135738051).

1211111000221 is an equidigital number, since it uses as much as digits as its factorization.

1211111000221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135738050.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 1211111000221 its reverse (1220001111121), we get a palindrome (2431112111342).

The spelling of 1211111000221 in words is "one trillion, two hundred eleven billion, one hundred eleven million, two hundred twenty-one", and thus it is an aban number.