21723893 has 8 divisors (see below), whose sum is σ = 21991200. Its totient is φ = 21458448.

The previous prime is 21723883. The next prime is 21723907. The reversal of 21723893 is 39832712.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21723893 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 (21723853) 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, 51638 + ... + 52056.

It is an arithmetic number, because the mean of its divisors is an integer number (2748900).

Almost surely, 2^21723893 is an apocalyptic number.

It is an amenable number.

21723893 is a deficient number, since it is larger than the sum of its proper divisors (267307).

21723893 is a wasteful number, since it uses less digits than its factorization.

21723893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 931.

The product of its digits is 18144, while the sum is 35.

The square root of 21723893 is about 4660.8897219308. The cubic root of 21723893 is about 279.0267785177.

The spelling of 21723893 in words is "twenty-one million, seven hundred twenty-three thousand, eight hundred ninety-three".