21723227 has 2 divisors, whose sum is σ = 21723228. Its totient is φ = 21723226.

The previous prime is 21723211. The next prime is 21723239. The reversal of 21723227 is 72232712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21723227 - 2⁴ = 21723211 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21723196 and 21723205.

It is not a weakly prime, because it can be changed into another prime (21723257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10861613 + 10861614.

It is an arithmetic number, because the mean of its divisors is an integer number (10861614).

Almost surely, 2^21723227 is an apocalyptic number.

21723227 is a deficient number, since it is larger than the sum of its proper divisors (1).

21723227 is an equidigital number, since it uses as much as digits as its factorization.

21723227 is an evil number, because the sum of its binary digits is even.

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

The square root of 21723227 is about 4660.8182757966. The cubic root of 21723227 is about 279.0239270684.

Adding to 21723227 its reverse (72232712), we get a palindrome (93955939).

The spelling of 21723227 in words is "twenty-one million, seven hundred twenty-three thousand, two hundred twenty-seven".