21696223 has 4 divisors (see below), whose sum is σ = 21749680. Its totient is φ = 21642768.

The previous prime is 21696217. The next prime is 21696277. The reversal of 21696223 is 32269612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21696223 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21696203) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26115 + ... + 26932.

It is an arithmetic number, because the mean of its divisors is an integer number (5437420).

Almost surely, 2^21696223 is an apocalyptic number.

21696223 is a deficient number, since it is larger than the sum of its proper divisors (53457).

21696223 is an equidigital number, since it uses as much as digits as its factorization.

21696223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53456.

The product of its digits is 7776, while the sum is 31.

The square root of 21696223 is about 4657.9204587455. The cubic root of 21696223 is about 278.9082615272.

The spelling of 21696223 in words is "twenty-one million, six hundred ninety-six thousand, two hundred twenty-three".