21323225 has 72 divisors (see below), whose sum is σ = 35622720. Its totient is φ = 12355200.

The previous prime is 21323209. The next prime is 21323261. The reversal of 21323225 is 52232312.

21323225 = 168² + 169² + ... + 409².

It is not a de Polignac number, because 21323225 - 2⁴ = 21323209 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21323197 and 21323206.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 402299 + ... + 402351.

It is an arithmetic number, because the mean of its divisors is an integer number (494760).

Almost surely, 2^21323225 is an apocalyptic number.

21323225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21323225 is a deficient number, since it is larger than the sum of its proper divisors (14299495).

21323225 is a wasteful number, since it uses less digits than its factorization.

21323225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111 (or 95 counting only the distinct ones).

The product of its digits is 720, while the sum is 20.

The square root of 21323225 is about 4617.7077646815. The cubic root of 21323225 is about 277.3006982768.

Adding to 21323225 its reverse (52232312), we get a palindrome (73555537).

The spelling of 21323225 in words is "twenty-one million, three hundred twenty-three thousand, two hundred twenty-five".