16520121 has 6 divisors (see below), whose sum is σ = 23862410. Its totient is φ = 11013408.

The previous prime is 16520099. The next prime is 16520137. The reversal of 16520121 is 12102561.

16520121 is a `hidden beast` number, since 1 + 652 + 0 + 12 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 10169721 + 6350400 = 3189^2 + 2520^2 .

It is not a de Polignac number, because 16520121 - 2⁹ = 16519609 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 16520094 and 16520103.

It is not an unprimeable number, because it can be changed into a prime (16520191) 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, 917776 + ... + 917793.

Almost surely, 2^16520121 is an apocalyptic number.

It is an amenable number.

16520121 is a deficient number, since it is larger than the sum of its proper divisors (7342289).

16520121 is a wasteful number, since it uses less digits than its factorization.

16520121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1835575 (or 1835572 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 16520121 is about 4064.4951716050. The cubic root of 16520121 is about 254.6856102410.

Adding to 16520121 its reverse (12102561), we get a palindrome (28622682).

It can be divided in two parts, 16520 and 121, that added together give a square (16641 = 129²).

The spelling of 16520121 in words is "sixteen million, five hundred twenty thousand, one hundred twenty-one".