71820 has 96 divisors (see below), whose sum is σ = 268800. Its totient is φ = 15552.

The previous prime is 71809. The next prime is 71821. The reversal of 71820 is 2817.

71820 = T₂₀ + T₂₁ + ... + T₇₅.

71820 = 12³ + 13³ + ... + 23³.

It is a super-2 number, since 2×71820² = 10316224800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 71793 and 71802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71821) by changing a digit.

71820 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3771 + ... + 3789.

It is an arithmetic number, because the mean of its divisors is an integer number (2800).

2⁷¹⁸²⁰ is an apocalyptic number.

71820 is a gapful number since it is divisible by the number (70) 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 71820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134400).

71820 is an abundant number, since it is smaller than the sum of its proper divisors (196980).

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

71820 is a wasteful number, since it uses less digits than its factorization.

71820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44 (or 36 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 71820 is about 267.9925372095. The cubic root of 71820 is about 41.5669794671.

The spelling of 71820 in words is "seventy-one thousand, eight hundred twenty".