81420 has 48 divisors (see below), whose sum is σ = 241920. Its totient is φ = 20416.

The previous prime is 81409. The next prime is 81421. The reversal of 81420 is 2418.

81420 = T₃₅ + T₃₆ + ... + T₈₀.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 81420.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81421) 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, 1351 + ... + 1409.

It is an arithmetic number, because the mean of its divisors is an integer number (5040).

2⁸¹⁴²⁰ 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 81420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120960).

81420 is an abundant number, since it is smaller than the sum of its proper divisors (160500).

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

81420 is a wasteful number, since it uses less digits than its factorization.

81420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94 (or 92 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 81420 is about 285.3419001829. The cubic root of 81420 is about 43.3421415362.

Adding to 81420 its reverse (2418), we get a palindrome (83838).

The spelling of 81420 in words is "eighty-one thousand, four hundred twenty".