21723269 has 8 divisors (see below), whose sum is σ = 22511520. Its totient is φ = 20949136.

The previous prime is 21723257. The next prime is 21723271. The reversal of 21723269 is 96232712.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21723269 - 2⁴ = 21723253 is a prime.

It is a super-2 number, since 2×21723269² = 943800832092722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21723239) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 347 + ... + 6600.

It is an arithmetic number, because the mean of its divisors is an integer number (2813940).

Almost surely, 2^21723269 is an apocalyptic number.

It is an amenable number.

21723269 is a deficient number, since it is larger than the sum of its proper divisors (788251).

21723269 is an equidigital number, since it uses as much as digits as its factorization.

21723269 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7059.

The product of its digits is 9072, while the sum is 32.

The square root of 21723269 is about 4660.8227814411. The cubic root of 21723269 is about 279.0241068913.

It can be divided in two parts, 2 and 1723269, that added together give a palindrome (1723271).

The spelling of 21723269 in words is "twenty-one million, seven hundred twenty-three thousand, two hundred sixty-nine".