7127987991 has 8 divisors (see below), whose sum is σ = 9509071104. Its totient is φ = 4749448440.

The previous prime is 7127987989. The next prime is 7127988011. The reversal of 7127987991 is 1997897217.

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

It is not a de Polignac number, because 7127987991 - 2¹ = 7127987989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7127987291) 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 7 ways as a sum of consecutive naturals, for example, 629341 + ... + 640566.

It is an arithmetic number, because the mean of its divisors is an integer number (1188633888).

Almost surely, 2^7127987991 is an apocalyptic number.

7127987991 is a deficient number, since it is larger than the sum of its proper divisors (2381083113).

7127987991 is a wasteful number, since it uses less digits than its factorization.

7127987991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1271781.

The product of its digits is 4000752, while the sum is 60.

The square root of 7127987991 is about 84427.4125565861. The cubic root of 7127987991 is about 1924.5195172090.

The spelling of 7127987991 in words is "seven billion, one hundred twenty-seven million, nine hundred eighty-seven thousand, nine hundred ninety-one".