21018325 has 6 divisors (see below), whose sum is σ = 26062754. Its totient is φ = 16814640.

The previous prime is 21018323. The next prime is 21018397. The reversal of 21018325 is 52381012.

It can be written as a sum of positive squares in 3 ways, for example, as 1153476 + 19864849 = 1074^2 + 4457^2 .

It is not a de Polignac number, because 21018325 - 2¹ = 21018323 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21018296 and 21018305.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21018323) 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, 420342 + ... + 420391.

Almost surely, 2^21018325 is an apocalyptic number.

21018325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21018325 is a deficient number, since it is larger than the sum of its proper divisors (5044429).

21018325 is an equidigital number, since it uses as much as digits as its factorization.

21018325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840743 (or 840738 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 21018325 is about 4584.5746803820. The cubic root of 21018325 is about 275.9726439665.

Adding to 21018325 its reverse (52381012), we get a palindrome (73399337).

The spelling of 21018325 in words is "twenty-one million, eighteen thousand, three hundred twenty-five".