81739682 has 4 divisors (see below), whose sum is σ = 122609526. Its totient is φ = 40869840.

The previous prime is 81739663. The next prime is 81739699. The reversal of 81739682 is 28693718.

It is a Cunningham number, because it is equal to 9041²+1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 28693718 = 2 ⋅14346859.

It can be written as a sum of positive squares in only one way, i.e., 81739681 + 1 = 9041^2 + 1^2 .

It is a super-2 number, since 2×81739682² = 13362751226922248, which contains 22 as substring.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 20434919 + ... + 20434922.

Almost surely, 2^81739682 is an apocalyptic number.

81739682 is a deficient number, since it is larger than the sum of its proper divisors (40869844).

81739682 is a wasteful number, since it uses less digits than its factorization.

81739682 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40869843.

The product of its digits is 145152, while the sum is 44.

The square root of 81739682 is about 9041.0000553036. Note that the first 4 decimals coincide. The cubic root of 81739682 is about 433.9879267809.

The spelling of 81739682 in words is "eighty-one million, seven hundred thirty-nine thousand, six hundred eighty-two".