28128656656 has 45 divisors (see below), whose sum is σ = 57003097879. Its totient is φ = 13445456288.

The previous prime is 28128656653. The next prime is 28128656707. The reversal of 28128656656 is 65665682182.

It is a happy number.

The square root of 28128656656 is 167716.

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

It is a super-2 number, since 2×28128656656² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28128656597 and 28128656606.

It is not an unprimeable number, because it can be changed into a prime (28128656653) 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, 15428961 + ... + 15430783.

Almost surely, 2^28128656656 is an apocalyptic number.

28128656656 is the 167716-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28128656656

28128656656 is an abundant number, since it is smaller than the sum of its proper divisors (28874441223).

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

28128656656 is an frugal number, since it uses more digits than its factorization.

28128656656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3700 (or 1848 counting only the distinct ones).

The product of its digits is 8294400, while the sum is 55.

The spelling of 28128656656 in words is "twenty-eight billion, one hundred twenty-eight million, six hundred fifty-six thousand, six hundred fifty-six".