81506028 has 12 divisors (see below), whose sum is σ = 190180760. Its totient is φ = 27168672.

The previous prime is 81505999. The next prime is 81506053. The reversal of 81506028 is 82060518.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 81505986 and 81506004.

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 in 3 ways as a sum of consecutive naturals, for example, 3396073 + ... + 3396096.

Almost surely, 2^81506028 is an apocalyptic number.

It is an amenable number.

81506028 is an abundant number, since it is smaller than the sum of its proper divisors (108674732).

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

81506028 is a wasteful number, since it uses less digits than its factorization.

81506028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6792176 (or 6792174 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 30.

The square root of 81506028 is about 9028.0688965027. The cubic root of 81506028 is about 433.5740119930.

The spelling of 81506028 in words is "eighty-one million, five hundred six thousand, twenty-eight".