28686535641 has 99 divisors (see below), whose sum is σ = 46851662653. Its totient is φ = 17560385280.

The previous prime is 28686535639. The next prime is 28686535643. The reversal of 28686535641 is 14653568682.

The square root of 28686535641 is 169371.

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

28686535641 is a `hidden beast` number, since 2 + 8 + 68 + 6 + 535 + 6 + 41 = 666.

It is an interprime number because it is at equal distance from previous prime (28686535639) and next prime (28686535643).

It can be written as a sum of positive squares in 4 ways, for example, as 2020952025 + 26665583616 = 44955^2 + 163296^2 .

It is not a de Polignac number, because 28686535641 - 2¹ = 28686535639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28686535643) by changing a digit.

It is a polite number, since it can be written in 98 ways as a sum of consecutive naturals, for example, 699671581 + ... + 699671621.

Almost surely, 2^28686535641 is an apocalyptic number.

28686535641 is the 169371-st square number.

28686535641 is the 84686-th centered octagonal number.

It is an amenable number.

28686535641 is a deficient number, since it is larger than the sum of its proper divisors (18165127012).

28686535641 is an frugal number, since it uses more digits than its factorization.

28686535641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146 (or 61 counting only the distinct ones).

The product of its digits is 8294400, while the sum is 54.

The spelling of 28686535641 in words is "twenty-eight billion, six hundred eighty-six million, five hundred thirty-five thousand, six hundred forty-one".