7728868686 has 48 divisors (see below), whose sum is σ = 19616135040. Its totient is φ = 2007497520.

The previous prime is 7728868663. The next prime is 7728868739. The reversal of 7728868686 is 6868688277.

It is a super-2 number, since 2×7728868686² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1191706 + ... + 1198173.

It is an arithmetic number, because the mean of its divisors is an integer number (408669480).

Almost surely, 2^7728868686 is an apocalyptic number.

7728868686 is an abundant number, since it is smaller than the sum of its proper divisors (11887266354).

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

7728868686 is a wasteful number, since it uses less digits than its factorization.

7728868686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2389909 (or 2389902 counting only the distinct ones).

The product of its digits is 86704128, while the sum is 66.

The square root of 7728868686 is about 87913.9845872089. The cubic root of 7728868686 is about 1977.1455558122.

The spelling of 7728868686 in words is "seven billion, seven hundred twenty-eight million, eight hundred sixty-eight thousand, six hundred eighty-six".