16520425 has 6 divisors (see below), whose sum is σ = 20485358. Its totient is φ = 13216320.

The previous prime is 16520377. The next prime is 16520429. The reversal of 16520425 is 52402561.

It can be written as a sum of positive squares in 3 ways, for example, as 44944 + 16475481 = 212^2 + 4059^2 .

It is not a de Polignac number, because 16520425 - 2¹¹ = 16518377 is a prime.

It is a super-3 number, since 3×16520425³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25), and also a Moran number because the ratio is a prime number: 660817 = 16520425 / (1 + 6 + 5 + 2 + 0 + 4 + 2 + 5).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16520425.

It is not an unprimeable number, because it can be changed into a prime (16520429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 330384 + ... + 330433.

Almost surely, 2^16520425 is an apocalyptic number.

It is an amenable number.

16520425 is a deficient number, since it is larger than the sum of its proper divisors (3964933).

16520425 is an equidigital number, since it uses as much as digits as its factorization.

16520425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660827 (or 660822 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 16520425 is about 4064.5325684511. The cubic root of 16520425 is about 254.6871724562.

Adding to 16520425 its reverse (52402561), we get a palindrome (68922986).

The spelling of 16520425 in words is "sixteen million, five hundred twenty thousand, four hundred twenty-five".