21117225 has 12 divisors (see below), whose sum is σ = 34913936. Its totient is φ = 11262480.

The previous prime is 21117223. The next prime is 21117233. The reversal of 21117225 is 52271112.

It is not a de Polignac number, because 21117225 - 2¹ = 21117223 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21117223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 140707 + ... + 140856.

Almost surely, 2^21117225 is an apocalyptic number.

21117225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21117225 is a deficient number, since it is larger than the sum of its proper divisors (13796711).

21117225 is a wasteful number, since it uses less digits than its factorization.

21117225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281576 (or 281571 counting only the distinct ones).

The product of its digits is 280, while the sum is 21.

The square root of 21117225 is about 4595.3481913779. The cubic root of 21117225 is about 276.4048223416.

Adding to 21117225 its reverse (52271112), we get a palindrome (73388337).

The spelling of 21117225 in words is "twenty-one million, one hundred seventeen thousand, two hundred twenty-five".