21223536 has 20 divisors (see below), whose sum is σ = 54827592. Its totient is φ = 7074496.

The previous prime is 21223519. The next prime is 21223583. The reversal of 21223536 is 63532212.

It is a Harshad number since it is a multiple of its sum of digits (24).

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, 221031 + ... + 221126.

Almost surely, 2^21223536 is an apocalyptic number.

It is an amenable number.

21223536 is an abundant number, since it is smaller than the sum of its proper divisors (33604056).

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

21223536 is a wasteful number, since it uses less digits than its factorization.

21223536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442168 (or 442162 counting only the distinct ones).

The product of its digits is 2160, while the sum is 24.

The square root of 21223536 is about 4606.9009105905. The cubic root of 21223536 is about 276.8678834921.

Adding to 21223536 its reverse (63532212), we get a palindrome (84755748).

The spelling of 21223536 in words is "twenty-one million, two hundred twenty-three thousand, five hundred thirty-six".