81589680 has 140 divisors (see below), whose sum is σ = 284617200. Its totient is φ = 21741696.

The previous prime is 81589657. The next prime is 81589693. The reversal of 81589680 is 8698518.

81589680 is a `hidden beast` number, since 8 + 1 + 589 + 68 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 57621 + ... + 59019.

It is an arithmetic number, because the mean of its divisors is an integer number (2032980).

Almost surely, 2^81589680 is an apocalyptic number.

81589680 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 81589680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142308600).

81589680 is an abundant number, since it is smaller than the sum of its proper divisors (203027520).

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

81589680 is a wasteful number, since it uses less digits than its factorization.

81589680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1430 (or 1409 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 45.

The square root of 81589680 is about 9032.7005928460. The cubic root of 81589680 is about 433.7222911372.

The spelling of 81589680 in words is "eighty-one million, five hundred eighty-nine thousand, six hundred eighty".