21310525 has 12 divisors (see below), whose sum is σ = 26789332. Its totient is φ = 16813440.

The previous prime is 21310519. The next prime is 21310561. The reversal of 21310525 is 52501312.

It can be written as a sum of positive squares in 6 ways, for example, as 168921 + 21141604 = 411^2 + 4598^2 .

It is not a de Polignac number, because 21310525 - 2³ = 21310517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4014 + ... + 7663.

Almost surely, 2^21310525 is an apocalyptic number.

21310525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21310525 is a deficient number, since it is larger than the sum of its proper divisors (5478807).

21310525 is a wasteful number, since it uses less digits than its factorization.

21310525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11760 (or 11755 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 21310525 is about 4616.3324187064. The cubic root of 21310525 is about 277.2456344005.

Adding to 21310525 its reverse (52501312), we get a palindrome (73811837).

The spelling of 21310525 in words is "twenty-one million, three hundred ten thousand, five hundred twenty-five".