81620 has 48 divisors (see below), whose sum is σ = 217728. Its totient is φ = 24960.

The previous prime is 81619. The next prime is 81629. The reversal of 81620 is 2618.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81620.

It is not an unprimeable number, because it can be changed into a prime (81629) 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, 1514 + ... + 1566.

It is an arithmetic number, because the mean of its divisors is an integer number (4536).

2⁸¹⁶²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108864).

81620 is an abundant number, since it is smaller than the sum of its proper divisors (136108).

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

81620 is a wasteful number, since it uses less digits than its factorization.

81620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80 (or 78 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 81620 is about 285.6921419990. The cubic root of 81620 is about 43.3776010477.

The spelling of 81620 in words is "eighty-one thousand, six hundred twenty".