81500028 has 24 divisors (see below), whose sum is σ = 190313088. Its totient is φ = 27145776.

The previous prime is 81499997. The next prime is 81500077. The reversal of 81500028 is 82000518.

It is a junction number, because it is equal to n+sod(n) for n = 81499980 and 81500007.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 27675 + ... + 30477.

It is an arithmetic number, because the mean of its divisors is an integer number (7929712).

Almost surely, 2^81500028 is an apocalyptic number.

It is an amenable number.

81500028 is an abundant number, since it is smaller than the sum of its proper divisors (108813060).

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

81500028 is a wasteful number, since it uses less digits than its factorization.

81500028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5233 (or 5231 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 81500028 is about 9027.7365934103. The cubic root of 81500028 is about 433.5633726658.

The spelling of 81500028 in words is "eighty-one million, five hundred thousand, twenty-eight".