6656991 has 16 divisors (see below), whose sum is σ = 9844608. Its totient is φ = 3967200.

The previous prime is 6656987. The next prime is 6657017. The reversal of 6656991 is 1996566.

It is not a de Polignac number, because 6656991 - 2² = 6656987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6656981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 360 + ... + 3666.

It is an arithmetic number, because the mean of its divisors is an integer number (615288).

Almost surely, 2^6656991 is an apocalyptic number.

6656991 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

6656991 is a deficient number, since it is larger than the sum of its proper divisors (3187617).

6656991 is a wasteful number, since it uses less digits than its factorization.

6656991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3382.

The product of its digits is 87480, while the sum is 42.

The square root of 6656991 is about 2580.1145323415. The cubic root of 6656991 is about 188.1161101821.

The spelling of 6656991 in words is "six million, six hundred fifty-six thousand, nine hundred ninety-one".