21296923 has 4 divisors (see below), whose sum is σ = 21325248. Its totient is φ = 21268600.

The previous prime is 21296921. The next prime is 21296939. The reversal of 21296923 is 32969212.

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 21296923 - 2¹ = 21296921 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21296921) 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, 13003 + ... + 14548.

It is an arithmetic number, because the mean of its divisors is an integer number (5331312).

Almost surely, 2^21296923 is an apocalyptic number.

21296923 is a deficient number, since it is larger than the sum of its proper divisors (28325).

21296923 is an equidigital number, since it uses as much as digits as its factorization.

21296923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28324.

The product of its digits is 11664, while the sum is 34.

The square root of 21296923 is about 4614.8589360889. The cubic root of 21296923 is about 277.1866354202.

The spelling of 21296923 in words is "twenty-one million, two hundred ninety-six thousand, nine hundred twenty-three".