121220111221591 has 2 divisors, whose sum is σ = 121220111221592. Its totient is φ = 121220111221590.

The previous prime is 121220111221553. The next prime is 121220111221607. The reversal of 121220111221591 is 195122111022121.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 121220111221591 - 2¹⁵ = 121220111188823 is a prime.

It is a super-3 number, since 3×121220111221591³ (a number of 43 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121220111221541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60610055610795 + 60610055610796.

It is an arithmetic number, because the mean of its divisors is an integer number (60610055610796).

Almost surely, 2^{121220111221591} is an apocalyptic number.

121220111221591 is a deficient number, since it is larger than the sum of its proper divisors (1).

121220111221591 is an equidigital number, since it uses as much as digits as its factorization.

121220111221591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 31.

The spelling of 121220111221591 in words is "one hundred twenty-one trillion, two hundred twenty billion, one hundred eleven million, two hundred twenty-one thousand, five hundred ninety-one".