81917193 has 32 divisors (see below), whose sum is σ = 116582400. Its totient is φ = 51097536.

The previous prime is 81917183. The next prime is 81917197. The reversal of 81917193 is 39171918.

It is not a de Polignac number, because 81917193 - 2¹⁴ = 81900809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81917197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 357603 + ... + 357831.

It is an arithmetic number, because the mean of its divisors is an integer number (3643200).

Almost surely, 2^81917193 is an apocalyptic number.

It is an amenable number.

81917193 is a deficient number, since it is larger than the sum of its proper divisors (34665207).

81917193 is a wasteful number, since it uses less digits than its factorization.

81917193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381.

The product of its digits is 13608, while the sum is 39.

The square root of 81917193 is about 9050.8117315520. The cubic root of 81917193 is about 434.3018580710.

The spelling of 81917193 in words is "eighty-one million, nine hundred seventeen thousand, one hundred ninety-three".