1221112111001 has 4 divisors (see below), whose sum is σ = 1222171185972. Its totient is φ = 1220053036032.

The previous prime is 1221112110997. The next prime is 1221112111007. The reversal of 1221112111001 is 1001112111221.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1143828111001 + 77284000000 = 1069499^2 + 278000^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221112111001 - 2² = 1221112110997 is a prime.

It is a super-2 number, since 2×1221112111001² (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 (1221112111007) 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, 529535756 + ... + 529538061.

It is an arithmetic number, because the mean of its divisors is an integer number (305542796493).

Almost surely, 2^{1221112111001} is an apocalyptic number.

It is an amenable number.

1221112111001 is a deficient number, since it is larger than the sum of its proper divisors (1059074971).

1221112111001 is a wasteful number, since it uses less digits than its factorization.

1221112111001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1059074970.

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

Adding to 1221112111001 its reverse (1001112111221), we get a palindrome (2222224222222).

The spelling of 1221112111001 in words is "one trillion, two hundred twenty-one billion, one hundred twelve million, one hundred eleven thousand, one".