28121277636 has 81 divisors (see below), whose sum is σ = 75073567023. Its totient is φ = 8874366480.

The previous prime is 28121277629. The next prime is 28121277673. The reversal of 28121277636 is 63677212182.

The square root of 28121277636 is 167694.

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

28121277636 is a `hidden beast` number, since 2 + 8 + 1 + 2 + 1 + 2 + 7 + 7 + 636 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 28121277591 and 28121277600.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 19116381 + ... + 19117851.

Almost surely, 2^28121277636 is an apocalyptic number.

28121277636 is the 167694-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28121277636

28121277636 is an abundant number, since it is smaller than the sum of its proper divisors (46952289387).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28121277636 is a wasteful number, since it uses less digits than its factorization.

28121277636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2990 (or 1495 counting only the distinct ones).

The product of its digits is 338688, while the sum is 45.

The spelling of 28121277636 in words is "twenty-eight billion, one hundred twenty-one million, two hundred seventy-seven thousand, six hundred thirty-six".