21330025 has 12 divisors (see below), whose sum is σ = 26535132. Its totient is φ = 17008640.

The previous prime is 21329999. The next prime is 21330047. The reversal of 21330025 is 52003312.

It can be written as a sum of positive squares in 6 ways, for example, as 316969 + 21013056 = 563^2 + 4584^2 .

It is not a de Polignac number, because 21330025 - 2⁹ = 21329513 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21329990 and 21330008.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7617 + ... + 10033.

It is an arithmetic number, because the mean of its divisors is an integer number (2211261).

Almost surely, 2^21330025 is an apocalyptic number.

21330025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21330025 is a deficient number, since it is larger than the sum of its proper divisors (5205107).

21330025 is a wasteful number, since it uses less digits than its factorization.

21330025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2780 (or 2775 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 16.

The square root of 21330025 is about 4618.4440020422. Note that the first 3 decimals coincide. The cubic root of 21330025 is about 277.3301723102.

Adding to 21330025 its reverse (52003312), we get a palindrome (73333337).

The spelling of 21330025 in words is "twenty-one million, three hundred thirty thousand, twenty-five".