1211112021221 has 4 divisors (see below), whose sum is σ = 1274854759200. Its totient is φ = 1147369283244.

The previous prime is 1211112021143. The next prime is 1211112021283. The reversal of 1211112021221 is 1221202111121.

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 not a de Polignac number, because 1211112021221 - 2²² = 1211107826917 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1211112021221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211112021121) 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, 31871368961 + ... + 31871368998.

It is an arithmetic number, because the mean of its divisors is an integer number (318713689800).

Almost surely, 2^{1211112021221} is an apocalyptic number.

It is an amenable number.

1211112021221 is a deficient number, since it is larger than the sum of its proper divisors (63742737979).

1211112021221 is an equidigital number, since it uses as much as digits as its factorization.

1211112021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63742737978.

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

Adding to 1211112021221 its reverse (1221202111121), we get a palindrome (2432314132342).

The spelling of 1211112021221 in words is "one trillion, two hundred eleven billion, one hundred twelve million, twenty-one thousand, two hundred twenty-one".