121221010091 has 4 divisors (see below), whose sum is σ = 121225059384. Its totient is φ = 121216960800.

The previous prime is 121221010087. The next prime is 121221010103. The reversal of 121221010091 is 190010122121.

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

It is a cyclic number.

It is not a de Polignac number, because 121221010091 - 2² = 121221010087 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121221010061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1979405 + ... + 2039726.

It is an arithmetic number, because the mean of its divisors is an integer number (30306264846).

Almost surely, 2^121221010091 is an apocalyptic number.

121221010091 is a deficient number, since it is larger than the sum of its proper divisors (4049293).

121221010091 is an equidigital number, since it uses as much as digits as its factorization.

121221010091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4049292.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 121221010091 in words is "one hundred twenty-one billion, two hundred twenty-one million, ten thousand, ninety-one".