16020056521 has 12 divisors (see below), whose sum is σ = 18820092420. Its totient is φ = 13595517600.

The previous prime is 16020056513. The next prime is 16020056543. The reversal of 16020056521 is 12565002061.

It can be written as a sum of positive squares in 2 ways, for example, as 15726414025 + 293642496 = 125405^2 + 17136^2 .

It is not a de Polignac number, because 16020056521 - 2³ = 16020056513 is a prime.

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 16020056521.

It is not an unprimeable number, because it can be changed into a prime (16020056551) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1613566 + ... + 1623463.

It is an arithmetic number, because the mean of its divisors is an integer number (1568341035).

Almost surely, 2^16020056521 is an apocalyptic number.

It is an amenable number.

16020056521 is a deficient number, since it is larger than the sum of its proper divisors (2800035899).

16020056521 is a wasteful number, since it uses less digits than its factorization.

16020056521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3237144 (or 3237137 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 28.

Adding to 16020056521 its reverse (12565002061), we get a palindrome (28585058582).

The spelling of 16020056521 in words is "sixteen billion, twenty million, fifty-six thousand, five hundred twenty-one".