28778406605 has 8 divisors (see below), whose sum is σ = 37190556312. Its totient is φ = 21251746368.

The previous prime is 28778406557. The next prime is 28778406697. The reversal of 28778406605 is 50660487782.

It can be written as a sum of positive squares in 4 ways, for example, as 1122384004 + 27656022601 = 33502^2 + 166301^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28778406605 - 2³⁴ = 11598537421 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 221372294 + ... + 221372423.

It is an arithmetic number, because the mean of its divisors is an integer number (4648819539).

Almost surely, 2^28778406605 is an apocalyptic number.

It is an amenable number.

28778406605 is a deficient number, since it is larger than the sum of its proper divisors (8412149707).

28778406605 is a wasteful number, since it uses less digits than its factorization.

28778406605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442744735.

The product of its (nonzero) digits is 4515840, while the sum is 53.

The spelling of 28778406605 in words is "twenty-eight billion, seven hundred seventy-eight million, four hundred six thousand, six hundred five".