121820 has 12 divisors (see below), whose sum is σ = 255864. Its totient is φ = 48720.

The previous prime is 121789. The next prime is 121843. The reversal of 121820 is 28121.

It is a super-2 number, since 2×121820² = 29680224800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 121795 and 121804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3026 + ... + 3065.

It is an arithmetic number, because the mean of its divisors is an integer number (21322).

2¹²¹⁸²⁰ is an apocalyptic number.

121820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121820 is an abundant number, since it is smaller than the sum of its proper divisors (134044).

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

121820 is a wasteful number, since it uses less digits than its factorization.

121820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6100 (or 6098 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 121820 is about 349.0272195689. The cubic root of 121820 is about 49.5723527851.

Adding to 121820 its reverse (28121), we get a palindrome (149941).

The spelling of 121820 in words is "one hundred twenty-one thousand, eight hundred twenty".