81442768 has 40 divisors (see below), whose sum is σ = 175408416. Its totient is φ = 36316800.

The previous prime is 81442717. The next prime is 81442789. The reversal of 81442768 is 86724418.

It is a self number, because there is not a number n which added to its sum of digits gives 81442768.

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, 4963 + ... + 13693.

Almost surely, 2^81442768 is an apocalyptic number.

81442768 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 81442768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87704208).

81442768 is an abundant number, since it is smaller than the sum of its proper divisors (93965648).

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

81442768 is a wasteful number, since it uses less digits than its factorization.

81442768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8803 (or 8797 counting only the distinct ones).

The product of its digits is 86016, while the sum is 40.

The square root of 81442768 is about 9024.5646986434. The cubic root of 81442768 is about 433.4618117395.

The spelling of 81442768 in words is "eighty-one million, four hundred forty-two thousand, seven hundred sixty-eight".