21214225 has 18 divisors (see below), whose sum is σ = 27271010. Its totient is φ = 16369920.

The previous prime is 21214187. The next prime is 21214229. The reversal of 21214225 is 52241212.

It can be written as a sum of positive squares in 9 ways, for example, as 6948496 + 14265729 = 2636^2 + 3777^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21214225 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21214229) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 20521 + ... + 21529.

Almost surely, 2^21214225 is an apocalyptic number.

21214225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21214225 is a deficient number, since it is larger than the sum of its proper divisors (6056785).

21214225 is a wasteful number, since it uses less digits than its factorization.

21214225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1077 (or 1043 counting only the distinct ones).

The product of its digits is 320, while the sum is 19.

The square root of 21214225 is about 4605.8902505379. The cubic root of 21214225 is about 276.8273892354.

Adding to 21214225 its reverse (52241212), we get a palindrome (73455437).

The spelling of 21214225 in words is "twenty-one million, two hundred fourteen thousand, two hundred twenty-five".