81990112 has 12 divisors (see below), whose sum is σ = 161418096. Its totient is φ = 40995040.

The previous prime is 81990107. The next prime is 81990143. The reversal of 81990112 is 21109918.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1281064 + ... + 1281127.

It is an arithmetic number, because the mean of its divisors is an integer number (13451508).

Almost surely, 2^81990112 is an apocalyptic number.

It is an amenable number.

81990112 is a deficient number, since it is larger than the sum of its proper divisors (79427984).

81990112 is a wasteful number, since it uses less digits than its factorization.

81990112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2562201 (or 2562193 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 81990112 is about 9054.8391482124. The cubic root of 81990112 is about 434.4306851786.

The spelling of 81990112 in words is "eighty-one million, nine hundred ninety thousand, one hundred twelve".