81589040 has 80 divisors (see below), whose sum is σ = 215090400. Its totient is φ = 28532736.

The previous prime is 81589037. The next prime is 81589043. The reversal of 81589040 is 4098518.

It is an interprime number because it is at equal distance from previous prime (81589037) and next prime (81589043).

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

It is not an unprimeable number, because it can be changed into a prime (81589043) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17696 + ... + 21824.

It is an arithmetic number, because the mean of its divisors is an integer number (2688630).

Almost surely, 2^81589040 is an apocalyptic number.

81589040 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 81589040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107545200).

81589040 is an abundant number, since it is smaller than the sum of its proper divisors (133501360).

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

81589040 is a wasteful number, since it uses less digits than its factorization.

81589040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4174 (or 4168 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 35.

The square root of 81589040 is about 9032.6651659408. The cubic root of 81589040 is about 433.7211570763.

The spelling of 81589040 in words is "eighty-one million, five hundred eighty-nine thousand, forty".