21383525 has 12 divisors (see below), whose sum is σ = 26881092. Its totient is φ = 16871040.

The previous prime is 21383503. The next prime is 21383573. The reversal of 21383525 is 52538312.

It can be written as a sum of positive squares in 6 ways, for example, as 4351396 + 17032129 = 2086^2 + 4127^2 .

It is not a de Polignac number, because 21383525 - 2⁸ = 21383269 is a prime.

It is a super-3 number, since 3×21383525³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4034 + ... + 7683.

It is an arithmetic number, because the mean of its divisors is an integer number (2240091).

Almost surely, 2^21383525 is an apocalyptic number.

21383525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21383525 is a deficient number, since it is larger than the sum of its proper divisors (5497567).

21383525 is a wasteful number, since it uses less digits than its factorization.

21383525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11800 (or 11795 counting only the distinct ones).

The product of its digits is 7200, while the sum is 29.

The square root of 21383525 is about 4624.2323687289. The cubic root of 21383525 is about 277.5618453722.

It can be divided in two parts, 213 and 83525, that added together give a palindrome (83738).

The spelling of 21383525 in words is "twenty-one million, three hundred eighty-three thousand, five hundred twenty-five".