21323504 has 10 divisors (see below), whose sum is σ = 41314320. Its totient is φ = 10661744.

The previous prime is 21323503. The next prime is 21323509. The reversal of 21323504 is 40532312.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323503) 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 as a sum of consecutive naturals, namely, 666344 + ... + 666375.

It is an arithmetic number, because the mean of its divisors is an integer number (4131432).

Almost surely, 2^21323504 is an apocalyptic number.

It is an amenable number.

21323504 is a deficient number, since it is larger than the sum of its proper divisors (19990816).

21323504 is a wasteful number, since it uses less digits than its factorization.

21323504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1332727 (or 1332721 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 21323504 is about 4617.7379743766. The cubic root of 21323504 is about 277.3019077023.

Adding to 21323504 its reverse (40532312), we get a palindrome (61855816).

The spelling of 21323504 in words is "twenty-one million, three hundred twenty-three thousand, five hundred four".