1221200010091 has 2 divisors, whose sum is σ = 1221200010092. Its totient is φ = 1221200010090.

The previous prime is 1221200010077. The next prime is 1221200010113. The reversal of 1221200010091 is 1900100021221.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221200010091 - 2¹⁷ = 1221199879019 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221200010001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610600005045 + 610600005046.

It is an arithmetic number, because the mean of its divisors is an integer number (610600005046).

Almost surely, 2^{1221200010091} is an apocalyptic number.

1221200010091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221200010091 is an equidigital number, since it uses as much as digits as its factorization.

1221200010091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 19.

The spelling of 1221200010091 in words is "one trillion, two hundred twenty-one billion, two hundred million, ten thousand, ninety-one".