201111551 has 2 divisors, whose sum is σ = 201111552. Its totient is φ = 201111550.

The previous prime is 201111541. The next prime is 201111553. The reversal of 201111551 is 155111102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 201111551 - 2²² = 196917247 is a prime.

Together with 201111553, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201111553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100555775 + 100555776.

It is an arithmetic number, because the mean of its divisors is an integer number (100555776).

Almost surely, 2^201111551 is an apocalyptic number.

201111551 is a deficient number, since it is larger than the sum of its proper divisors (1).

201111551 is an equidigital number, since it uses as much as digits as its factorization.

201111551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 50, while the sum is 17.

The square root of 201111551 is about 14181.3804335121. The cubic root of 201111551 is about 585.8849450098.

Adding to 201111551 its reverse (155111102), we get a palindrome (356222653).

The spelling of 201111551 in words is "two hundred one million, one hundred eleven thousand, five hundred fifty-one".