16521225 has 24 divisors (see below), whose sum is σ = 31218240. Its totient is φ = 7552320.

The previous prime is 16521223. The next prime is 16521227. The reversal of 16521225 is 52212561.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (16521223) and next prime (16521227).

It is not a de Polignac number, because 16521225 - 2¹ = 16521223 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 16521195 and 16521204.

It is not an unprimeable number, because it can be changed into a prime (16521221) 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, 15210 + ... + 16259.

It is an arithmetic number, because the mean of its divisors is an integer number (1300760).

Almost surely, 2^16521225 is an apocalyptic number.

16521225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16521225 is a deficient number, since it is larger than the sum of its proper divisors (14697015).

16521225 is a wasteful number, since it uses less digits than its factorization.

16521225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31489 (or 31484 counting only the distinct ones).

The product of its digits is 1200, while the sum is 24.

The square root of 16521225 is about 4064.6309795601. The cubic root of 16521225 is about 254.6912834572.

Adding to 16521225 its reverse (52212561), we get a palindrome (68733786).

The spelling of 16521225 in words is "sixteen million, five hundred twenty-one thousand, two hundred twenty-five".