21223025 has 6 divisors (see below), whose sum is σ = 26316582. Its totient is φ = 16978400.

The previous prime is 21223009. The next prime is 21223051. The reversal of 21223025 is 52032212.

It can be written as a sum of positive squares in 3 ways, for example, as 53824 + 21169201 = 232^2 + 4601^2 .

It is not a de Polignac number, because 21223025 - 2⁴ = 21223009 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21222994 and 21223012.

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, 424436 + ... + 424485.

It is an arithmetic number, because the mean of its divisors is an integer number (4386097).

Almost surely, 2^21223025 is an apocalyptic number.

21223025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21223025 is a deficient number, since it is larger than the sum of its proper divisors (5093557).

21223025 is an equidigital number, since it uses as much as digits as its factorization.

21223025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 848931 (or 848926 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 21223025 is about 4606.8454499798. The cubic root of 21223025 is about 276.8656614209.

Adding to 21223025 its reverse (52032212), we get a palindrome (73255237).

The spelling of 21223025 in words is "twenty-one million, two hundred twenty-three thousand, twenty-five".