1221121000191 has 16 divisors (see below), whose sum is σ = 1648100079360. Its totient is φ = 804171532800.

The previous prime is 1221121000171. The next prime is 1221121000199. The reversal of 1221121000191 is 1910001211221.

It is not a de Polignac number, because 1221121000191 - 2⁷ = 1221121000063 is a prime.

It is a super-2 number, since 2×1221121000191² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221121000199) 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 15 ways as a sum of consecutive naturals, for example, 7448610 + ... + 7610783.

It is an arithmetic number, because the mean of its divisors is an integer number (103006254960).

Almost surely, 2^{1221121000191} is an apocalyptic number.

1221121000191 is a deficient number, since it is larger than the sum of its proper divisors (426979079169).

1221121000191 is a wasteful number, since it uses less digits than its factorization.

1221121000191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15059726.

The product of its (nonzero) digits is 72, while the sum is 21.

The spelling of 1221121000191 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-one million, one hundred ninety-one", and thus it is an aban number.