1221111001211 has 4 divisors (see below), whose sum is σ = 1221313546800. Its totient is φ = 1220908455624.

The previous prime is 1221111001151. The next prime is 1221111001237. The reversal of 1221111001211 is 1121001111221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221111001211 - 2¹⁸ = 1221110739067 is a prime.

It is a super-2 number, since 2×1221111001211² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221111001261) 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, 101263751 + ... + 101275808.

It is an arithmetic number, because the mean of its divisors is an integer number (305328386700).

Almost surely, 2^{1221111001211} is an apocalyptic number.

1221111001211 is a deficient number, since it is larger than the sum of its proper divisors (202545589).

1221111001211 is an equidigital number, since it uses as much as digits as its factorization.

1221111001211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202545588.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 1221111001211 its reverse (1121001111221), we get a palindrome (2342112112432).

The spelling of 1221111001211 in words is "one trillion, two hundred twenty-one billion, one hundred eleven million, one thousand, two hundred eleven".