21006325 has 6 divisors (see below), whose sum is σ = 26047874. Its totient is φ = 16805040.

The previous prime is 21006311. The next prime is 21006329. The reversal of 21006325 is 52360012.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 194481 + 20811844 = 441^2 + 4562^2 .

It is not a de Polignac number, because 21006325 - 2⁹ = 21005813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21006329) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 420102 + ... + 420151.

Almost surely, 2^21006325 is an apocalyptic number.

21006325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21006325 is a deficient number, since it is larger than the sum of its proper divisors (5041549).

21006325 is an equidigital number, since it uses as much as digits as its factorization.

21006325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840263 (or 840258 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21006325 is about 4583.2657570776. The cubic root of 21006325 is about 275.9201135806.

Adding to 21006325 its reverse (52360012), we get a palindrome (73366337).

The spelling of 21006325 in words is "twenty-one million, six thousand, three hundred twenty-five".