21252319 has 24 divisors (see below), whose sum is σ = 24744384. Its totient is φ = 18216000.

The previous prime is 21252293. The next prime is 21252323. The reversal of 21252319 is 91325212.

It is a happy number.

It is not a de Polignac number, because 21252319 - 2¹⁵ = 21219551 is a prime.

It is a super-3 number, since 3×21252319³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 21252293 and 21252302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21252349) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 210369 + ... + 210469.

It is an arithmetic number, because the mean of its divisors is an integer number (1031016).

Almost surely, 2^21252319 is an apocalyptic number.

21252319 is a deficient number, since it is larger than the sum of its proper divisors (3492065).

21252319 is a wasteful number, since it uses less digits than its factorization.

21252319 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207 (or 196 counting only the distinct ones).

The product of its digits is 1080, while the sum is 25.

The square root of 21252319 is about 4610.0237526503. The cubic root of 21252319 is about 276.9929881320.

It can be divided in two parts, 2125 and 2319, that added together give a palindrome (4444).

The spelling of 21252319 in words is "twenty-one million, two hundred fifty-two thousand, three hundred nineteen".