191551 has 2 divisors, whose sum is σ = 191552. Its totient is φ = 191550.

The previous prime is 191537. The next prime is 191561. The reversal of 191551 is 155191.

It is a strong prime.

It is an emirp because it is prime and its reverse (155191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191551 - 2⁵ = 191519 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95775 + 95776.

It is an arithmetic number, because the mean of its divisors is an integer number (95776).

2¹⁹¹⁵⁵¹ is an apocalyptic number.

191551 is a deficient number, since it is larger than the sum of its proper divisors (1).

191551 is an equidigital number, since it uses as much as digits as its factorization.

191551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 225, while the sum is 22.

The square root of 191551 is about 437.6653973071. The cubic root of 191551 is about 57.6449775690.

The spelling of 191551 in words is "one hundred ninety-one thousand, five hundred fifty-one".