6481991 has 2 divisors, whose sum is σ = 6481992. Its totient is φ = 6481990.

The previous prime is 6481963. The next prime is 6481997. The reversal of 6481991 is 1991846.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6481991 - 2⁶ = 6481927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6481997) 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, 3240995 + 3240996.

It is an arithmetic number, because the mean of its divisors is an integer number (3240996).

Almost surely, 2^6481991 is an apocalyptic number.

6481991 is a deficient number, since it is larger than the sum of its proper divisors (1).

6481991 is an equidigital number, since it uses as much as digits as its factorization.

6481991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 38.

The square root of 6481991 is about 2545.9754515706. The cubic root of 6481991 is about 186.4530425375.

The spelling of 6481991 in words is "six million, four hundred eighty-one thousand, nine hundred ninety-one".