81686526 has 8 divisors (see below), whose sum is σ = 163373064. Its totient is φ = 27228840.

The previous prime is 81686459. The next prime is 81686531. The reversal of 81686526 is 62568618.

It is a sphenic number, since it is the product of 3 distinct primes.

81686526 is an admirable number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6807205 + ... + 6807216.

It is an arithmetic number, because the mean of its divisors is an integer number (20421633).

Almost surely, 2^81686526 is an apocalyptic number.

81686526 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81686526 is a wasteful number, since it uses less digits than its factorization.

81686526 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13614426.

The product of its digits is 138240, while the sum is 42.

The square root of 81686526 is about 9038.0598581775. The cubic root of 81686526 is about 433.8938310526.

The spelling of 81686526 in words is "eighty-one million, six hundred eighty-six thousand, five hundred twenty-six".