21420226 has 4 divisors (see below), whose sum is σ = 32130342. Its totient is φ = 10710112.

The previous prime is 21420209. The next prime is 21420227. The reversal of 21420226 is 62202412.

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

It can be written as a sum of positive squares in only one way, i.e., 18361225 + 3059001 = 4285^2 + 1749^2 .

It is not an unprimeable number, because it can be changed into a prime (21420227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5355055 + ... + 5355058.

Almost surely, 2^21420226 is an apocalyptic number.

21420226 is a deficient number, since it is larger than the sum of its proper divisors (10710116).

21420226 is a wasteful number, since it uses less digits than its factorization.

21420226 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10710115.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 21420226 is about 4628.1990017716. The cubic root of 21420226 is about 277.7205497158.

Adding to 21420226 its reverse (62202412), we get a palindrome (83622638).

The spelling of 21420226 in words is "twenty-one million, four hundred twenty thousand, two hundred twenty-six".