112821 has 4 divisors (see below), whose sum is σ = 150432. Its totient is φ = 75212.

The previous prime is 112807. The next prime is 112831. The reversal of 112821 is 128211.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 128211 = 3 ⋅42737.

It is a cyclic number.

It is not a de Polignac number, because 112821 - 2⁶ = 112757 is a prime.

It is a D-number.

112821 is a lucky number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 112821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (112831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18801 + ... + 18806.

It is an arithmetic number, because the mean of its divisors is an integer number (37608).

2¹¹²⁸²¹ is an apocalyptic number.

It is an amenable number.

112821 is a deficient number, since it is larger than the sum of its proper divisors (37611).

112821 is an equidigital number, since it uses as much as digits as its factorization.

112821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37610.

The product of its digits is 32, while the sum is 15.

The square root of 112821 is about 335.8883743150. Note that the first 3 decimals coincide. The cubic root of 112821 is about 48.3203400138.

The spelling of 112821 in words is "one hundred twelve thousand, eight hundred twenty-one".