81751648 has 48 divisors (see below), whose sum is σ = 180354384. Its totient is φ = 36149760.

The previous prime is 81751613. The next prime is 81751687. The reversal of 81751648 is 84615718.

It is a self number, because there is not a number n which added to its sum of digits gives 81751648.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9886 + ... + 16162.

It is an arithmetic number, because the mean of its divisors is an integer number (3757383).

Almost surely, 2^81751648 is an apocalyptic number.

81751648 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81751648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90177192).

81751648 is an abundant number, since it is smaller than the sum of its proper divisors (98602736).

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

81751648 is a wasteful number, since it uses less digits than its factorization.

81751648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6335 (or 6327 counting only the distinct ones).

The product of its digits is 53760, while the sum is 40.

The square root of 81751648 is about 9041.6617941615. The cubic root of 81751648 is about 434.0091031382.

The spelling of 81751648 in words is "eighty-one million, seven hundred fifty-one thousand, six hundred forty-eight".