101820 has 24 divisors (see below), whose sum is σ = 285264. Its totient is φ = 27136.

The previous prime is 101807. The next prime is 101833. The reversal of 101820 is 28101.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (101807) and next prime (101833).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 101796 and 101805.

It is a congruent number.

It is an unprimeable number.

101820 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 7 ways as a sum of consecutive naturals, for example, 789 + ... + 908.

It is an arithmetic number, because the mean of its divisors is an integer number (11886).

2¹⁰¹⁸²⁰ is an apocalyptic number.

101820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

101820 is an abundant number, since it is smaller than the sum of its proper divisors (183444).

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

101820 is a wasteful number, since it uses less digits than its factorization.

101820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1709 (or 1707 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 101820 is about 319.0924630887. The cubic root of 101820 is about 46.6957868138.

Adding to 101820 its reverse (28101), we get a palindrome (129921).

It can be divided in two parts, 10 and 1820, that added together give a triangular number (1830 = T₆₀).

The spelling of 101820 in words is "one hundred one thousand, eight hundred twenty".