106821 has 24 divisors (see below), whose sum is σ = 183456. Its totient is φ = 59040.

The previous prime is 106801. The next prime is 106823. The reversal of 106821 is 128601.

It is not a de Polignac number, because 106821 - 2⁷ = 106693 is a prime.

It is a super-2 number, since 2×106821² = 22821452082, which contains 22 as substring.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 106794 and 106803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (106823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1246 + ... + 1328.

It is an arithmetic number, because the mean of its divisors is an integer number (7644).

2¹⁰⁶⁸²¹ is an apocalyptic number.

106821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

106821 is a deficient number, since it is larger than the sum of its proper divisors (76635).

106821 is a wasteful number, since it uses less digits than its factorization.

106821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 106821 is about 326.8348206663. The cubic root of 106821 is about 47.4481058374.

It can be divided in two parts, 1068 and 21, that added together give a square (1089 = 33²).

The spelling of 106821 in words is "one hundred six thousand, eight hundred twenty-one".