21696224 has 24 divisors (see below), whose sum is σ = 46598328. Its totient is φ = 9861760.

The previous prime is 21696217. The next prime is 21696277. The reversal of 21696224 is 42269612.

It is a super-2 number, since 2×21696224² = 941452271716352, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

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, 30467 + ... + 31170.

It is an arithmetic number, because the mean of its divisors is an integer number (1941597).

Almost surely, 2^21696224 is an apocalyptic number.

It is an amenable number.

21696224 is an abundant number, since it is smaller than the sum of its proper divisors (24902104).

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

21696224 is a wasteful number, since it uses less digits than its factorization.

21696224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61658 (or 61650 counting only the distinct ones).

The product of its digits is 10368, while the sum is 32.

The square root of 21696224 is about 4657.9205660896. The cubic root of 21696224 is about 278.9082658123.

The spelling of 21696224 in words is "twenty-one million, six hundred ninety-six thousand, two hundred twenty-four".