81050191 has 2 divisors, whose sum is σ = 81050192. Its totient is φ = 81050190.

The previous prime is 81050161. The next prime is 81050201. The reversal of 81050191 is 19105018.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81050191 - 2⁹ = 81049679 is a prime.

It is a super-2 number, since 2×81050191² = 13138266922272962, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81050131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40525095 + 40525096.

It is an arithmetic number, because the mean of its divisors is an integer number (40525096).

Almost surely, 2^81050191 is an apocalyptic number.

81050191 is a deficient number, since it is larger than the sum of its proper divisors (1).

81050191 is an equidigital number, since it uses as much as digits as its factorization.

81050191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 25.

The square root of 81050191 is about 9002.7879570720. The cubic root of 81050191 is about 432.7642204771.

The spelling of 81050191 in words is "eighty-one million, fifty thousand, one hundred ninety-one".