21525225 has 12 divisors (see below), whose sum is σ = 35588496. Its totient is φ = 11480080.

The previous prime is 21525223. The next prime is 21525227. The reversal of 21525225 is 52252512.

It is an interprime number because it is at equal distance from previous prime (21525223) and next prime (21525227).

It is not a de Polignac number, because 21525225 - 2¹ = 21525223 is a prime.

It is a super-2 number, since 2×21525225² = 926670622601250, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21525195 and 21525204.

It is not an unprimeable number, because it can be changed into a prime (21525223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 143427 + ... + 143576.

It is an arithmetic number, because the mean of its divisors is an integer number (2965708).

Almost surely, 2^21525225 is an apocalyptic number.

21525225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21525225 is a deficient number, since it is larger than the sum of its proper divisors (14063271).

21525225 is a wasteful number, since it uses less digits than its factorization.

21525225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287016 (or 287011 counting only the distinct ones).

The product of its digits is 2000, while the sum is 24.

The square root of 21525225 is about 4639.5285320817. The cubic root of 21525225 is about 278.1735929067.

Adding to 21525225 its reverse (52252512), we get a palindrome (73777737).

The spelling of 21525225 in words is "twenty-one million, five hundred twenty-five thousand, two hundred twenty-five".