21146225 has 6 divisors (see below), whose sum is σ = 26221350. Its totient is φ = 16916960.

The previous prime is 21146207. The next prime is 21146231. The reversal of 21146225 is 52264112.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 3236401 + 17909824 = 1799^2 + 4232^2 .

It is not a de Polignac number, because 21146225 - 2⁶ = 21146161 is a prime.

It is a super-6 number, since 6×21146225⁶ (a number of 45 digits) contains 666666 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21146225.

It is an unprimeable number.

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 in 5 ways as a sum of consecutive naturals, for example, 422900 + ... + 422949.

It is an arithmetic number, because the mean of its divisors is an integer number (4370225).

Almost surely, 2^21146225 is an apocalyptic number.

21146225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21146225 is a deficient number, since it is larger than the sum of its proper divisors (5075125).

21146225 is an equidigital number, since it uses as much as digits as its factorization.

21146225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 845859 (or 845854 counting only the distinct ones).

The product of its digits is 960, while the sum is 23.

The square root of 21146225 is about 4598.5024736320. The cubic root of 21146225 is about 276.5312921365.

The spelling of 21146225 in words is "twenty-one million, one hundred forty-six thousand, two hundred twenty-five".