21525125 has 16 divisors (see below), whose sum is σ = 28035072. Its totient is φ = 16469200.

The previous prime is 21525121. The next prime is 21525139. The reversal of 21525125 is 52152512.

It is not a de Polignac number, because 21525125 - 2² = 21525121 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21525125.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21525121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 869 + ... + 6618.

It is an arithmetic number, because the mean of its divisors is an integer number (1752192).

Almost surely, 2^21525125 is an apocalyptic number.

21525125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21525125 is a deficient number, since it is larger than the sum of its proper divisors (6509947).

21525125 is an equidigital number, since it uses as much as digits as its factorization.

21525125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7525 (or 7515 counting only the distinct ones).

The product of its digits is 1000, while the sum is 23.

The square root of 21525125 is about 4639.5177551121. The cubic root of 21525125 is about 278.1731621345.

Adding to 21525125 its reverse (52152512), we get a palindrome (73677637).

The spelling of 21525125 in words is "twenty-one million, five hundred twenty-five thousand, one hundred twenty-five".