28617779887 has 4 divisors (see below), whose sum is σ = 28619325000. Its totient is φ = 28616234776.

The previous prime is 28617779863. The next prime is 28617779891. The reversal of 28617779887 is 78897771682.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28617779887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28617779837) 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, 744433 + ... + 781930.

It is an arithmetic number, because the mean of its divisors is an integer number (7154831250).

Almost surely, 2^28617779887 is an apocalyptic number.

28617779887 is a deficient number, since it is larger than the sum of its proper divisors (1545113).

28617779887 is a wasteful number, since it uses less digits than its factorization.

28617779887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1545112.

The product of its digits is 132765696, while the sum is 70.

The spelling of 28617779887 in words is "twenty-eight billion, six hundred seventeen million, seven hundred seventy-nine thousand, eight hundred eighty-seven".