6888139991 has 4 divisors (see below), whose sum is σ = 6926621400. Its totient is φ = 6849658584.

The previous prime is 6888139987. The next prime is 6888140003. The reversal of 6888139991 is 1999318886.

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 6888139991 - 2² = 6888139987 is a prime.

It is a super-2 number, since 2×6888139991² = 94892945071226960162, which 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 (6888139931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19240436 + ... + 19240793.

It is an arithmetic number, because the mean of its divisors is an integer number (1731655350).

Almost surely, 2^6888139991 is an apocalyptic number.

6888139991 is a deficient number, since it is larger than the sum of its proper divisors (38481409).

6888139991 is a wasteful number, since it uses less digits than its factorization.

6888139991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38481408.

The product of its digits is 6718464, while the sum is 62.

The square root of 6888139991 is about 82994.8190611920. The cubic root of 6888139991 is about 1902.6868718103.

The spelling of 6888139991 in words is "six billion, eight hundred eighty-eight million, one hundred thirty-nine thousand, nine hundred ninety-one".