12099821 has 4 divisors (see below), whose sum is σ = 12357312. Its totient is φ = 11842332.

The previous prime is 12099809. The next prime is 12099839. The reversal of 12099821 is 12899021.

It is a happy number.

12099821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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: 12899021 = 23 ⋅560827.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12099821 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 (12099221) 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, 128675 + ... + 128768.

It is an arithmetic number, because the mean of its divisors is an integer number (3089328).

Almost surely, 2^12099821 is an apocalyptic number.

It is an amenable number.

12099821 is a deficient number, since it is larger than the sum of its proper divisors (257491).

12099821 is an equidigital number, since it uses as much as digits as its factorization.

12099821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257490.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 12099821 is about 3478.4796966491. The cubic root of 12099821 is about 229.5759103869.

The spelling of 12099821 in words is "twelve million, ninety-nine thousand, eight hundred twenty-one".