108213821 has 4 divisors (see below), whose sum is σ = 108678492. Its totient is φ = 107749152.

The previous prime is 108213811. The next prime is 108213841. The reversal of 108213821 is 128312801.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 128312801 = 421 ⋅304781.

It can be written as a sum of positive squares in 2 ways, for example, as 74736025 + 33477796 = 8645^2 + 5786^2 .

It is a cyclic number.

It is not a de Polignac number, because 108213821 - 2¹⁸ = 107951677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (108213811) 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, 231986 + ... + 232451.

It is an arithmetic number, because the mean of its divisors is an integer number (27169623).

Almost surely, 2^108213821 is an apocalyptic number.

It is an amenable number.

108213821 is a deficient number, since it is larger than the sum of its proper divisors (464671).

108213821 is an equidigital number, since it uses as much as digits as its factorization.

108213821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 464670.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 108213821 is about 10402.5872262625. The cubic root of 108213821 is about 476.5343858954.

The spelling of 108213821 in words is "one hundred eight million, two hundred thirteen thousand, eight hundred twenty-one".