81859760 has 80 divisors (see below), whose sum is σ = 210361536. Its totient is φ = 29466624.

The previous prime is 81859753. The next prime is 81859787. The reversal of 81859760 is 6795818.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29972 + ... + 32588.

Almost surely, 2^81859760 is an apocalyptic number.

81859760 is a gapful number since it is divisible by the number (80) 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 81859760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105180768).

81859760 is an abundant number, since it is smaller than the sum of its proper divisors (128501776).

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

81859760 is a wasteful number, since it uses less digits than its factorization.

81859760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2670 (or 2664 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 44.

The square root of 81859760 is about 9047.6383658942. The cubic root of 81859760 is about 434.2003364844.

The spelling of 81859760 in words is "eighty-one million, eight hundred fifty-nine thousand, seven hundred sixty".