1221221112001 has 16 divisors (see below), whose sum is σ = 1395077068800. Its totient is φ = 1058178931920.

The previous prime is 1221221111993. The next prime is 1221221112043. The reversal of 1221221112001 is 1002111221221.

It is not a de Polignac number, because 1221221112001 - 2³ = 1221221111993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221221112071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8456601 + ... + 8599798.

It is an arithmetic number, because the mean of its divisors is an integer number (87192316800).

Almost surely, 2^{1221221112001} is an apocalyptic number.

1221221112001 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221221112001 is a deficient number, since it is larger than the sum of its proper divisors (173855956799).

1221221112001 is a wasteful number, since it uses less digits than its factorization.

1221221112001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17056716.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221221112001 its reverse (1002111221221), we get a palindrome (2223332333222).

The spelling of 1221221112001 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, one hundred twelve thousand, one".