201105991 has 2 divisors, whose sum is σ = 201105992. Its totient is φ = 201105990.

The previous prime is 201105967. The next prime is 201106007. The reversal of 201105991 is 199501102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 201105991 - 2¹⁷ = 200974919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201115991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100552995 + 100552996.

It is an arithmetic number, because the mean of its divisors is an integer number (100552996).

Almost surely, 2^201105991 is an apocalyptic number.

201105991 is a deficient number, since it is larger than the sum of its proper divisors (1).

201105991 is an equidigital number, since it uses as much as digits as its factorization.

201105991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 810, while the sum is 28.

The square root of 201105991 is about 14181.1844004653. The cubic root of 201105991 is about 585.8795457669.

It can be divided in two parts, 20 and 1105991, that added together give a palindrome (1106011).

The spelling of 201105991 in words is "two hundred one million, one hundred five thousand, nine hundred ninety-one".