1211101001221 has 4 divisors (see below), whose sum is σ = 1274843159200. Its totient is φ = 1147358843244.

The previous prime is 1211101001219. The next prime is 1211101001237. The reversal of 1211101001221 is 1221001011121.

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 not a de Polignac number, because 1211101001221 - 2¹ = 1211101001219 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211101001261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31871078961 + ... + 31871078998.

It is an arithmetic number, because the mean of its divisors is an integer number (318710789800).

Almost surely, 2^{1211101001221} is an apocalyptic number.

It is an amenable number.

1211101001221 is a deficient number, since it is larger than the sum of its proper divisors (63742157979).

1211101001221 is an equidigital number, since it uses as much as digits as its factorization.

1211101001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63742157978.

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

Adding to 1211101001221 its reverse (1221001011121), we get a palindrome (2432102012342).

The spelling of 1211101001221 in words is "one trillion, two hundred eleven billion, one hundred one million, one thousand, two hundred twenty-one".