28126979521 has 3 divisors (see below), whose sum is σ = 28127147233. Its totient is φ = 28126811810.

The previous prime is 28126979483. The next prime is 28126979527. The reversal of 28126979521 is 12597962182.

The square root of 28126979521 is 167711.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 28126979521 - 2⁷ = 28126979393 is a prime.

It is a super-2 number, since 2×28126979521² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28126979527) 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 2 ways as a sum of consecutive naturals, for example, 83856 + ... + 251566.

Almost surely, 2^28126979521 is an apocalyptic number.

28126979521 is the 167711-st square number.

28126979521 is the 83856-th centered octagonal number.

It is an amenable number.

28126979521 is a deficient number, since it is larger than the sum of its proper divisors (167712).

28126979521 is an frugal number, since it uses more digits than its factorization.

28126979521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 335422 (or 167711 counting only the distinct ones).

The product of its digits is 1088640, while the sum is 52.

The spelling of 28126979521 in words is "twenty-eight billion, one hundred twenty-six million, nine hundred seventy-nine thousand, five hundred twenty-one".