21730227 has 4 divisors (see below), whose sum is σ = 28973640. Its totient is φ = 14486816.

The previous prime is 21730169. The next prime is 21730249. The reversal of 21730227 is 72203712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21730227 - 2⁷ = 21730099 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21730197 and 21730206.

It is not an unprimeable number, because it can be changed into a prime (21730277) 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, 3621702 + ... + 3621707.

It is an arithmetic number, because the mean of its divisors is an integer number (7243410).

Almost surely, 2^21730227 is an apocalyptic number.

21730227 is a deficient number, since it is larger than the sum of its proper divisors (7243413).

21730227 is an equidigital number, since it uses as much as digits as its factorization.

21730227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7243412.

The product of its (nonzero) digits is 1176, while the sum is 24.

The square root of 21730227 is about 4661.5691564107. The cubic root of 21730227 is about 279.0538943431.

Adding to 21730227 its reverse (72203712), we get a palindrome (93933939).

The spelling of 21730227 in words is "twenty-one million, seven hundred thirty thousand, two hundred twenty-seven".