21954223 has 4 divisors (see below), whose sum is σ = 21964680. Its totient is φ = 21943768.

The previous prime is 21954211. The next prime is 21954227. The reversal of 21954223 is 32245912.

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 a de Polignac number, because none of the positive numbers 2^k-21954223 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21954191 and 21954200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21954227) 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, 865 + ... + 6682.

It is an arithmetic number, because the mean of its divisors is an integer number (5491170).

Almost surely, 2^21954223 is an apocalyptic number.

21954223 is a deficient number, since it is larger than the sum of its proper divisors (10457).

21954223 is an equidigital number, since it uses as much as digits as its factorization.

21954223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10456.

The product of its digits is 4320, while the sum is 28.

The square root of 21954223 is about 4685.5333741208. The cubic root of 21954223 is about 280.0094512116.

The spelling of 21954223 in words is "twenty-one million, nine hundred fifty-four thousand, two hundred twenty-three".