1221211220111 has 8 divisors (see below), whose sum is σ = 1238466253824. Its totient is φ = 1204064368920.

The previous prime is 1221211220081. The next prime is 1221211220123. The reversal of 1221211220111 is 1110221121221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221211220111 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221211220111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221211220171) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27022895 + ... + 27068048.

It is an arithmetic number, because the mean of its divisors is an integer number (154808281728).

Almost surely, 2^{1221211220111} is an apocalyptic number.

1221211220111 is a deficient number, since it is larger than the sum of its proper divisors (17255033713).

1221211220111 is a wasteful number, since it uses less digits than its factorization.

1221211220111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54091261.

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

Adding to 1221211220111 its reverse (1110221121221), we get a palindrome (2331432341332).

The spelling of 1221211220111 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, two hundred twenty thousand, one hundred eleven".