21323569 has 4 divisors (see below), whose sum is σ = 21355120. Its totient is φ = 21292020.

The previous prime is 21323531. The next prime is 21323591. The reversal of 21323569 is 96532312.

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.

It is a cyclic number.

It is not a de Polignac number, because 21323569 - 2⁷ = 21323441 is a prime.

It is a super-2 number, since 2×21323569² = 909389189795522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21323569.

It is not an unprimeable number, because it can be changed into a prime (21323509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14739 + ... + 16120.

It is an arithmetic number, because the mean of its divisors is an integer number (5338780).

Almost surely, 2^21323569 is an apocalyptic number.

It is an amenable number.

21323569 is a deficient number, since it is larger than the sum of its proper divisors (31551).

21323569 is an equidigital number, since it uses as much as digits as its factorization.

21323569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31550.

The product of its digits is 9720, while the sum is 31.

The square root of 21323569 is about 4617.7450124493. The cubic root of 21323569 is about 277.3021894666.

The spelling of 21323569 in words is "twenty-one million, three hundred twenty-three thousand, five hundred sixty-nine".