6991087 has 4 divisors (see below), whose sum is σ = 7109640. Its totient is φ = 6872536.

The previous prime is 6991043. The next prime is 6991091. The reversal of 6991087 is 7801996.

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 6991087 - 2⁷ = 6990959 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6991687) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59188 + ... + 59305.

It is an arithmetic number, because the mean of its divisors is an integer number (1777410).

Almost surely, 2^6991087 is an apocalyptic number.

6991087 is a deficient number, since it is larger than the sum of its proper divisors (118553).

6991087 is a wasteful number, since it uses less digits than its factorization.

6991087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118552.

The product of its (nonzero) digits is 27216, while the sum is 40.

The square root of 6991087 is about 2644.0663758688. The cubic root of 6991087 is about 191.2118935285.

It can be divided in two parts, 699108 and 7, that multiplied together give a triangular number (4893756 = T₃₁₂₈).

The spelling of 6991087 in words is "six million, nine hundred ninety-one thousand, eighty-seven".