28489726521 has 9 divisors (see below), whose sum is σ = 41152558629. Its totient is φ = 18992813436.

The previous prime is 28489726513. The next prime is 28489726541. The reversal of 28489726521 is 12562798482.

The square root of 28489726521 is 168789.

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

28489726521 is a `hidden beast` number, since 2 + 8 + 4 + 8 + 97 + 26 + 521 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 28489726521 - 2³ = 28489726513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28489726501) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 478236 + ... + 534498.

Almost surely, 2^28489726521 is an apocalyptic number.

28489726521 is the 168789-th square number.

28489726521 is the 84395-th centered octagonal number.

It is an amenable number.

28489726521 is a deficient number, since it is larger than the sum of its proper divisors (12662832108).

28489726521 is an frugal number, since it uses more digits than its factorization.

28489726521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112532 (or 56266 counting only the distinct ones).

The product of its digits is 3870720, while the sum is 54.

The spelling of 28489726521 in words is "twenty-eight billion, four hundred eighty-nine million, seven hundred twenty-six thousand, five hundred twenty-one".