21943123 has 4 divisors (see below), whose sum is σ = 21952600. Its totient is φ = 21933648.

The previous prime is 21943099. The next prime is 21943171. The reversal of 21943123 is 32134912.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21943123 - 2⁵ = 21943091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21943193) 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, 1303 + ... + 6751.

It is an arithmetic number, because the mean of its divisors is an integer number (5488150).

Almost surely, 2^21943123 is an apocalyptic number.

21943123 is a deficient number, since it is larger than the sum of its proper divisors (9477).

21943123 is an equidigital number, since it uses as much as digits as its factorization.

21943123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9476.

The product of its digits is 1296, while the sum is 25.

The square root of 21943123 is about 4684.3487274113. The cubic root of 21943123 is about 279.9622525645.

The spelling of 21943123 in words is "twenty-one million, nine hundred forty-three thousand, one hundred twenty-three".