21707423 has 4 divisors (see below), whose sum is σ = 22651248. Its totient is φ = 20763600.

The previous prime is 21707417. The next prime is 21707429. The reversal of 21707423 is 32470712.

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

It is an interprime number because it is at equal distance from previous prime (21707417) and next prime (21707429).

It is a cyclic number.

It is not a de Polignac number, because 21707423 - 2⁴ = 21707407 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21707392 and 21707401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21707429) 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, 471878 + ... + 471923.

It is an arithmetic number, because the mean of its divisors is an integer number (5662812).

Almost surely, 2^21707423 is an apocalyptic number.

21707423 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21707423 is a deficient number, since it is larger than the sum of its proper divisors (943825).

21707423 is an equidigital number, since it uses as much as digits as its factorization.

21707423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 943824.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 21707423 is about 4659.1225568770. The cubic root of 21707423 is about 278.9562458418.

The spelling of 21707423 in words is "twenty-one million, seven hundred seven thousand, four hundred twenty-three".