7957991 has 2 divisors, whose sum is σ = 7957992. Its totient is φ = 7957990.

The previous prime is 7957987. The next prime is 7958009. The reversal of 7957991 is 1997597.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 7957991 - 2² = 7957987 is a 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 (7957951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3978995 + 3978996.

It is an arithmetic number, because the mean of its divisors is an integer number (3978996).

Almost surely, 2^7957991 is an apocalyptic number.

7957991 is a deficient number, since it is larger than the sum of its proper divisors (1).

7957991 is an equidigital number, since it uses as much as digits as its factorization.

7957991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 178605, while the sum is 47.

The square root of 7957991 is about 2820.9911378804. The cubic root of 7957991 is about 199.6493104436.

The spelling of 7957991 in words is "seven million, nine hundred fifty-seven thousand, nine hundred ninety-one".