28122751521 has 24 divisors (see below), whose sum is σ = 42403672896. Its totient is φ = 17926682400.

The previous prime is 28122751507. The next prime is 28122751549. The reversal of 28122751521 is 12515722182.

28122751521 is a `hidden beast` number, since 2 + 8 + 122 + 7 + 5 + 1 + 521 = 666.

It is not a de Polignac number, because 28122751521 - 2⁶ = 28122751457 is a prime.

It is a super-2 number, since 2×28122751521² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28122751571) 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, 566331 + ... + 613983.

It is an arithmetic number, because the mean of its divisors is an integer number (1766819704).

Almost surely, 2^28122751521 is an apocalyptic number.

It is an amenable number.

28122751521 is a deficient number, since it is larger than the sum of its proper divisors (14280921375).

28122751521 is a wasteful number, since it uses less digits than its factorization.

28122751521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50533 (or 50530 counting only the distinct ones).

The product of its digits is 22400, while the sum is 36.

The spelling of 28122751521 in words is "twenty-eight billion, one hundred twenty-two million, seven hundred fifty-one thousand, five hundred twenty-one".