81785360 has 40 divisors (see below), whose sum is σ = 193748760. Its totient is φ = 32095232.

The previous prime is 81785357. The next prime is 81785369. The reversal of 81785360 is 6358718.

It can be written as a sum of positive squares in 4 ways, for example, as 21381376 + 60403984 = 4624^2 + 7772^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×81785360² = 13377690220659200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81785369) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5405 + ... + 13884.

It is an arithmetic number, because the mean of its divisors is an integer number (4843719).

Almost surely, 2^81785360 is an apocalyptic number.

81785360 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81785360 is an abundant number, since it is smaller than the sum of its proper divisors (111963400).

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

81785360 is a wasteful number, since it uses less digits than its factorization.

81785360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19355 (or 19349 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 38.

The square root of 81785360 is about 9043.5258610787. The cubic root of 81785360 is about 434.0687525134.

The spelling of 81785360 in words is "eighty-one million, seven hundred eighty-five thousand, three hundred sixty".