81201191 has 2 divisors, whose sum is σ = 81201192. Its totient is φ = 81201190.

The previous prime is 81201181. The next prime is 81201223. The reversal of 81201191 is 19110218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81201191 - 2²² = 77006887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81201181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40600595 + 40600596.

It is an arithmetic number, because the mean of its divisors is an integer number (40600596).

Almost surely, 2^81201191 is an apocalyptic number.

81201191 is a deficient number, since it is larger than the sum of its proper divisors (1).

81201191 is an equidigital number, since it uses as much as digits as its factorization.

81201191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 23.

The square root of 81201191 is about 9011.1703457431. The cubic root of 81201191 is about 433.0328065502.

The spelling of 81201191 in words is "eighty-one million, two hundred one thousand, one hundred ninety-one".