28520116641 has 27 divisors (see below), whose sum is σ = 42255780697. Its totient is φ = 18536159040.

The previous prime is 28520116621. The next prime is 28520116663. The reversal of 28520116641 is 14661102582.

It is a happy number.

The square root of 28520116641 is 168879.

It is a perfect power (a square), and thus also a powerful number.

28520116641 is a `hidden beast` number, since 2 + 8 + 5 + 2 + 0 + 1 + 1 + 6 + 641 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 364619025 + 28155497616 = 19095^2 + 167796^2 .

It is not a de Polignac number, because 28520116641 - 2⁵ = 28520116609 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28520116596 and 28520116605.

It is not an unprimeable number, because it can be changed into a prime (28520116621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 20771431 + ... + 20772803.

Almost surely, 2^28520116641 is an apocalyptic number.

28520116641 is the 168879-th square number.

28520116641 is the 84440-th centered octagonal number.

It is an amenable number.

28520116641 is a deficient number, since it is larger than the sum of its proper divisors (13735664056).

28520116641 is an frugal number, since it uses more digits than its factorization.

28520116641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2834 (or 1417 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

Multiplying 28520116641 by its sum of digits (36), we get a square (1026724199076 = 1013274²).

It can be divided in two parts, 28520 and 116641, that added together give a square (145161 = 381²).

The spelling of 28520116641 in words is "twenty-eight billion, five hundred twenty million, one hundred sixteen thousand, six hundred forty-one".