191015291 has 2 divisors, whose sum is σ = 191015292. Its totient is φ = 191015290.

The previous prime is 191015261. The next prime is 191015309. The reversal of 191015291 is 192510191.

It is a strong prime.

It is an emirp because it is prime and its reverse (192510191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191015291 - 2¹⁰ = 191014267 is a prime.

It is not a weakly prime, because it can be changed into another prime (191015261) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95507645 + 95507646.

It is an arithmetic number, because the mean of its divisors is an integer number (95507646).

Almost surely, 2^191015291 is an apocalyptic number.

191015291 is a deficient number, since it is larger than the sum of its proper divisors (1).

191015291 is an equidigital number, since it uses as much as digits as its factorization.

191015291 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 29.

The square root of 191015291 is about 13820.8281589780. The cubic root of 191015291 is about 575.9118899353.

The spelling of 191015291 in words is "one hundred ninety-one million, fifteen thousand, two hundred ninety-one".