6457991 has 2 divisors, whose sum is σ = 6457992. Its totient is φ = 6457990.

The previous prime is 6457987. The next prime is 6458003. The reversal of 6457991 is 1997546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6457991 - 2² = 6457987 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6457921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3228995 + 3228996.

It is an arithmetic number, because the mean of its divisors is an integer number (3228996).

Almost surely, 2^6457991 is an apocalyptic number.

6457991 is a deficient number, since it is larger than the sum of its proper divisors (1).

6457991 is an equidigital number, since it uses as much as digits as its factorization.

6457991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68040, while the sum is 41.

The square root of 6457991 is about 2541.2577594569. The cubic root of 6457991 is about 186.2226397057. Note that the first 3 decimals are identical.

The spelling of 6457991 in words is "six million, four hundred fifty-seven thousand, nine hundred ninety-one".