81628560 has 480 divisors, whose sum is σ = 341228160. Its totient is φ = 17915904.

The previous prime is 81628523. The next prime is 81628571. The reversal of 81628560 is 6582618.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 4296231 + ... + 4296249.

It is an arithmetic number, because the mean of its divisors is an integer number (710892).

Almost surely, 2^81628560 is an apocalyptic number.

81628560 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 81628560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (170614080).

81628560 is an abundant number, since it is smaller than the sum of its proper divisors (259599600).

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

81628560 is a wasteful number, since it uses less digits than its factorization.

81628560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77 (or 59 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 81628560 is about 9034.8525167819. The cubic root of 81628560 is about 433.7911742148.

The spelling of 81628560 in words is "eighty-one million, six hundred twenty-eight thousand, five hundred sixty".