81749179 has 6 divisors (see below), whose sum is σ = 82992084. Its totient is φ = 80524620.

The previous prime is 81749167. The next prime is 81749189. The reversal of 81749179 is 97194718.

It is not a de Polignac number, because 81749179 - 2⁵ = 81749147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81749119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4617 + ... + 13594.

It is an arithmetic number, because the mean of its divisors is an integer number (13832014).

Almost surely, 2^81749179 is an apocalyptic number.

81749179 is a deficient number, since it is larger than the sum of its proper divisors (1242905).

81749179 is an equidigital number, since it uses as much as digits as its factorization.

81749179 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18345 (or 18278 counting only the distinct ones).

The product of its digits is 127008, while the sum is 46.

The square root of 81749179 is about 9041.5252584948. The cubic root of 81749179 is about 434.0047338919.

The spelling of 81749179 in words is "eighty-one million, seven hundred forty-nine thousand, one hundred seventy-nine".