81828686 has 4 divisors (see below), whose sum is σ = 122743032. Its totient is φ = 40914342.

The previous prime is 81828673. The next prime is 81828697. The reversal of 81828686 is 68682818.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 68682818 = 2 ⋅34341409.

It is a self number, because there is not a number n which added to its sum of digits gives 81828686.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 20457170 + ... + 20457173.

It is an arithmetic number, because the mean of its divisors is an integer number (30685758).

Almost surely, 2^81828686 is an apocalyptic number.

81828686 is a deficient number, since it is larger than the sum of its proper divisors (40914346).

81828686 is a wasteful number, since it uses less digits than its factorization.

81828686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40914345.

The product of its digits is 294912, while the sum is 47.

The square root of 81828686 is about 9045.9209591948. The cubic root of 81828686 is about 434.1453886531.

The spelling of 81828686 in words is "eighty-one million, eight hundred twenty-eight thousand, six hundred eighty-six".