201220111221991 has 2 divisors, whose sum is σ = 201220111221992. Its totient is φ = 201220111221990.

The previous prime is 201220111221967. The next prime is 201220111222027. The reversal of 201220111221991 is 199122111022102.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 201220111221991 - 2⁵ = 201220111221959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201220111227991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100610055610995 + 100610055610996.

It is an arithmetic number, because the mean of its divisors is an integer number (100610055610996).

Almost surely, 2^{201220111221991} is an apocalyptic number.

201220111221991 is a deficient number, since it is larger than the sum of its proper divisors (1).

201220111221991 is an equidigital number, since it uses as much as digits as its factorization.

201220111221991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 34.

The spelling of 201220111221991 in words is "two hundred one trillion, two hundred twenty billion, one hundred eleven million, two hundred twenty-one thousand, nine hundred ninety-one".