21696503 has 4 divisors (see below), whose sum is σ = 22225728. Its totient is φ = 21167280.

The previous prime is 21696491. The next prime is 21696511. The reversal of 21696503 is 30569612.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21696503 - 2⁴ = 21696487 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21696503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21696583) 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, 264551 + ... + 264632.

It is an arithmetic number, because the mean of its divisors is an integer number (5556432).

Almost surely, 2^21696503 is an apocalyptic number.

21696503 is a deficient number, since it is larger than the sum of its proper divisors (529225).

21696503 is an equidigital number, since it uses as much as digits as its factorization.

21696503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 529224.

The product of its (nonzero) digits is 9720, while the sum is 32.

The square root of 21696503 is about 4657.9505149797. The cubic root of 21696503 is about 278.9094613363.

The spelling of 21696503 in words is "twenty-one million, six hundred ninety-six thousand, five hundred three".