1221111101001 has 12 divisors (see below), whose sum is σ = 1789617371696. Its totient is φ = 740067333720.

The previous prime is 1221111100997. The next prime is 1221111101029. The reversal of 1221111101001 is 1001011111221.

It is not a de Polignac number, because 1221111101001 - 2² = 1221111100997 is a prime.

It is a super-2 number, since 2×1221111101001² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1221111101051) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1681970851 + ... + 1681971576.

Almost surely, 2^{1221111101001} is an apocalyptic number.

1221111101001 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221111101001 is a deficient number, since it is larger than the sum of its proper divisors (568506270695).

1221111101001 is a wasteful number, since it uses less digits than its factorization.

1221111101001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3363942452 (or 3363942441 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 12.

Adding to 1221111101001 its reverse (1001011111221), we get a palindrome (2222122212222).

The spelling of 1221111101001 in words is "one trillion, two hundred twenty-one billion, one hundred eleven million, one hundred one thousand, one".