7728868687 has 4 divisors (see below), whose sum is σ = 8064906480. Its totient is φ = 7392830896.

The previous prime is 7728868663. The next prime is 7728868739. The reversal of 7728868687 is 7868688277.

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

It is a cyclic number.

It is not a de Polignac number, because 7728868687 - 2¹⁹ = 7728344399 is a prime.

It is a super-2 number, since 2×7728868687² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7728868187) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 168018862 + ... + 168018907.

It is an arithmetic number, because the mean of its divisors is an integer number (2016226620).

Almost surely, 2^7728868687 is an apocalyptic number.

7728868687 is a deficient number, since it is larger than the sum of its proper divisors (336037793).

7728868687 is a wasteful number, since it uses less digits than its factorization.

7728868687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336037792.

The product of its digits is 101154816, while the sum is 67.

The square root of 7728868687 is about 87913.9845928963. The cubic root of 7728868687 is about 1977.1455558975.

The spelling of 7728868687 in words is "seven billion, seven hundred twenty-eight million, eight hundred sixty-eight thousand, six hundred eighty-seven".