28778235653 has 4 divisors (see below), whose sum is σ = 28901747628. Its totient is φ = 28654723680.

The previous prime is 28778235649. The next prime is 28778235671. The reversal of 28778235653 is 35653287782.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12254932804 + 16523302849 = 110702^2 + 128543^2 .

It is a cyclic number.

It is not a de Polignac number, because 28778235653 - 2² = 28778235649 is a prime.

It is a super-3 number, since 3×28778235653³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28778235683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61755638 + ... + 61756103.

It is an arithmetic number, because the mean of its divisors is an integer number (7225436907).

Almost surely, 2^28778235653 is an apocalyptic number.

It is an amenable number.

28778235653 is a deficient number, since it is larger than the sum of its proper divisors (123511975).

28778235653 is a wasteful number, since it uses less digits than its factorization.

28778235653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123511974.

The product of its digits is 16934400, while the sum is 56.

The spelling of 28778235653 in words is "twenty-eight billion, seven hundred seventy-eight million, two hundred thirty-five thousand, six hundred fifty-three".