81170091 has 6 divisors (see below), whose sum is σ = 117245700. Its totient is φ = 54113388.

The previous prime is 81170057. The next prime is 81170129. The reversal of 81170091 is 19007118.

It is not a de Polignac number, because 81170091 - 2⁶ = 81170027 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81170591) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4509441 + ... + 4509458.

It is an arithmetic number, because the mean of its divisors is an integer number (19540950).

Almost surely, 2^81170091 is an apocalyptic number.

81170091 is a deficient number, since it is larger than the sum of its proper divisors (36075609).

81170091 is a wasteful number, since it uses less digits than its factorization.

81170091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9018905 (or 9018902 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 27.

The square root of 81170091 is about 9009.4445444766. Note that the first 3 decimals coincide. The cubic root of 81170091 is about 432.9775157357.

The spelling of 81170091 in words is "eighty-one million, one hundred seventy thousand, ninety-one".