21263225 has 6 divisors (see below), whose sum is σ = 26366430. Its totient is φ = 17010560.

The previous prime is 21263213. The next prime is 21263233. The reversal of 21263225 is 52236212.

It can be written as a sum of positive squares in 3 ways, for example, as 204304 + 21058921 = 452^2 + 4589^2 .

It is not a de Polignac number, because 21263225 - 2⁶ = 21263161 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21263225.

It is an unprimeable number.

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, 425240 + ... + 425289.

It is an arithmetic number, because the mean of its divisors is an integer number (4394405).

Almost surely, 2^21263225 is an apocalyptic number.

21263225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21263225 is a deficient number, since it is larger than the sum of its proper divisors (5103205).

21263225 is an equidigital number, since it uses as much as digits as its factorization.

21263225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 850539 (or 850534 counting only the distinct ones).

The product of its digits is 1440, while the sum is 23.

The square root of 21263225 is about 4611.2064581842. The cubic root of 21263225 is about 277.0403612985.

Adding to 21263225 its reverse (52236212), we get a palindrome (73499437).

The spelling of 21263225 in words is "twenty-one million, two hundred sixty-three thousand, two hundred twenty-five".