6435991 has 2 divisors, whose sum is σ = 6435992. Its totient is φ = 6435990.

The previous prime is 6435983. The next prime is 6435997. The reversal of 6435991 is 1995346.

6435991 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6435991 - 2³ = 6435983 is a prime.

It is a Chen prime.

6435991 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 6435991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6435997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3217995 + 3217996.

It is an arithmetic number, because the mean of its divisors is an integer number (3217996).

Almost surely, 2^6435991 is an apocalyptic number.

6435991 is a deficient number, since it is larger than the sum of its proper divisors (1).

6435991 is an equidigital number, since it uses as much as digits as its factorization.

6435991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29160, while the sum is 37.

The square root of 6435991 is about 2536.9255014683. The cubic root of 6435991 is about 186.0109351108.

The spelling of 6435991 in words is "six million, four hundred thirty-five thousand, nine hundred ninety-one".