21225025 has 12 divisors (see below), whose sum is σ = 26563900. Its totient is φ = 16822080.

The previous prime is 21224989. The next prime is 21225037. The reversal of 21225025 is 52052212.

It can be written as a sum of positive squares in 6 ways, for example, as 576 + 21224449 = 24^2 + 4607^2 .

It is not a de Polignac number, because 21225025 - 2¹¹ = 21222977 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21224993 and 21225011.

It is a congruent number.

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, 1170 + ... + 6619.

Almost surely, 2^21225025 is an apocalyptic number.

21225025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21225025 is a deficient number, since it is larger than the sum of its proper divisors (5338875).

21225025 is a wasteful number, since it uses less digits than its factorization.

21225025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7908 (or 7903 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 21225025 is about 4607.0625131422. The cubic root of 21225025 is about 276.8743581693.

Adding to 21225025 its reverse (52052212), we get a palindrome (73277237).

The spelling of 21225025 in words is "twenty-one million, two hundred twenty-five thousand, twenty-five".