21525375 has 32 divisors (see below), whose sum is σ = 36444096. Its totient is φ = 11280000.

The previous prime is 21525373. The next prime is 21525403. The reversal of 21525375 is 57352512.

It is not a de Polignac number, because 21525375 - 2¹ = 21525373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21525373) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22405 + ... + 23345.

It is an arithmetic number, because the mean of its divisors is an integer number (1138878).

Almost surely, 2^21525375 is an apocalyptic number.

21525375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21525375 is a deficient number, since it is larger than the sum of its proper divisors (14918721).

21525375 is an equidigital number, since it uses as much as digits as its factorization.

With its successor (21525376) it forms a Ruth-Aaron pair, since the sum of their distinct prime factors is the same (1010).

21525375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1020 (or 1010 counting only the distinct ones).

The product of its digits is 10500, while the sum is 30.

The square root of 21525375 is about 4639.5446974892. The cubic root of 21525375 is about 278.1742390624.

Adding to 21525375 its reverse (57352512), we get a palindrome (78877887).

The spelling of 21525375 in words is "twenty-one million, five hundred twenty-five thousand, three hundred seventy-five".