21819227 has 2 divisors, whose sum is σ = 21819228. Its totient is φ = 21819226.

The previous prime is 21819209. The next prime is 21819241. The reversal of 21819227 is 72291812.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21819227 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21819193 and 21819202.

It is not a weakly prime, because it can be changed into another prime (21819527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10909613 + 10909614.

It is an arithmetic number, because the mean of its divisors is an integer number (10909614).

Almost surely, 2^21819227 is an apocalyptic number.

21819227 is a deficient number, since it is larger than the sum of its proper divisors (1).

21819227 is an equidigital number, since it uses as much as digits as its factorization.

21819227 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 32.

The square root of 21819227 is about 4671.1055436588. The cubic root of 21819227 is about 279.4343469889.

The spelling of 21819227 in words is "twenty-one million, eight hundred nineteen thousand, two hundred twenty-seven".