21223704 has 16 divisors (see below), whose sum is σ = 53059320. Its totient is φ = 7074560.

The previous prime is 21223693. The next prime is 21223711. The reversal of 21223704 is 40732212.

It is a super-2 number, since 2×21223704² = 900891222959232, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 442137 + ... + 442184.

Almost surely, 2^21223704 is an apocalyptic number.

21223704 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21223704 is an abundant number, since it is smaller than the sum of its proper divisors (31835616).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21223704 is a wasteful number, since it uses less digits than its factorization.

21223704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 884330 (or 884326 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 21223704 is about 4606.9191440701. The cubic root of 21223704 is about 276.8686140282.

Adding to 21223704 its reverse (40732212), we get a palindrome (61955916).

The spelling of 21223704 in words is "twenty-one million, two hundred twenty-three thousand, seven hundred four".