6406691 has 2 divisors, whose sum is σ = 6406692. Its totient is φ = 6406690.

The previous prime is 6406681. The next prime is 6406717. The reversal of 6406691 is 1966046.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6406691 - 2²² = 2212387 is a prime.

It is not a weakly prime, because it can be changed into another prime (6406601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3203345 + 3203346.

It is an arithmetic number, because the mean of its divisors is an integer number (3203346).

Almost surely, 2^6406691 is an apocalyptic number.

6406691 is a deficient number, since it is larger than the sum of its proper divisors (1).

6406691 is an equidigital number, since it uses as much as digits as its factorization.

6406691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 6406691 is about 2531.1442076658. The cubic root of 6406691 is about 185.7282326240.

The spelling of 6406691 in words is "six million, four hundred six thousand, six hundred ninety-one".