6709991 has 4 divisors (see below), whose sum is σ = 6941400. Its totient is φ = 6478584.

The previous prime is 6709979. The next prime is 6710009. The reversal of 6709991 is 1999076.

It is a happy number.

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 6709991 - 2¹⁰ = 6708967 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 (6709921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 115661 + ... + 115718.

It is an arithmetic number, because the mean of its divisors is an integer number (1735350).

Almost surely, 2^6709991 is an apocalyptic number.

6709991 is a deficient number, since it is larger than the sum of its proper divisors (231409).

6709991 is a wasteful number, since it uses less digits than its factorization.

6709991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231408.

The product of its (nonzero) digits is 30618, while the sum is 41.

The square root of 6709991 is about 2590.3650321914. The cubic root of 6709991 is about 188.6140233756.

Subtracting from 6709991 its reverse (1999076), we obtain a triangular number (4710915 = T₃₀₆₉).

The spelling of 6709991 in words is "six million, seven hundred nine thousand, nine hundred ninety-one".