21420227 has 2 divisors, whose sum is σ = 21420228. Its totient is φ = 21420226.

The previous prime is 21420209. The next prime is 21420233. The reversal of 21420227 is 72202412.

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-21420227 is a prime.

It is a super-2 number, since 2×21420227² = 917652249463058, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21420199 and 21420208.

It is not a weakly prime, because it can be changed into another prime (21420257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710113 + 10710114.

It is an arithmetic number, because the mean of its divisors is an integer number (10710114).

Almost surely, 2^21420227 is an apocalyptic number.

21420227 is a deficient number, since it is larger than the sum of its proper divisors (1).

21420227 is an equidigital number, since it uses as much as digits as its factorization.

21420227 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 21420227 is about 4628.1991098050. The cubic root of 21420227 is about 277.7205540376.

Adding to 21420227 its reverse (72202412), we get a palindrome (93622639).

The spelling of 21420227 in words is "twenty-one million, four hundred twenty thousand, two hundred twenty-seven".