21109323 has 16 divisors (see below), whose sum is σ = 29792000. Its totient is φ = 13258080.

The previous prime is 21109321. The next prime is 21109327. The reversal of 21109323 is 32390112.

It is a happy number.

It is not a de Polignac number, because 21109323 - 2¹ = 21109321 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21109323.

It is not an unprimeable number, because it can be changed into a prime (21109321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10413 + ... + 12273.

It is an arithmetic number, because the mean of its divisors is an integer number (1862000).

Almost surely, 2^21109323 is an apocalyptic number.

21109323 is a deficient number, since it is larger than the sum of its proper divisors (8682677).

21109323 is a wasteful number, since it uses less digits than its factorization.

21109323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2082.

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 21109323 is about 4594.4883284213. The cubic root of 21109323 is about 276.3703414317.

Adding to 21109323 its reverse (32390112), we get a palindrome (53499435).

The spelling of 21109323 in words is "twenty-one million, one hundred nine thousand, three hundred twenty-three".