21667225 has 6 divisors (see below), whose sum is σ = 26867390. Its totient is φ = 17333760.

The previous prime is 21667223. The next prime is 21667253. The reversal of 21667225 is 52276612.

It can be written as a sum of positive squares in 3 ways, for example, as 100489 + 21566736 = 317^2 + 4644^2 .

It is not a de Polignac number, because 21667225 - 2¹ = 21667223 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21667223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 433320 + ... + 433369.

Almost surely, 2^21667225 is an apocalyptic number.

21667225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21667225 is a deficient number, since it is larger than the sum of its proper divisors (5200165).

21667225 is an equidigital number, since it uses as much as digits as its factorization.

21667225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 866699 (or 866694 counting only the distinct ones).

The product of its digits is 10080, while the sum is 31.

The square root of 21667225 is about 4654.8066554906. The cubic root of 21667225 is about 278.7839482205.

The spelling of 21667225 in words is "twenty-one million, six hundred sixty-seven thousand, two hundred twenty-five".