8601991 has 2 divisors, whose sum is σ = 8601992. Its totient is φ = 8601990.

The previous prime is 8601979. The next prime is 8601997. The reversal of 8601991 is 1991068.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 8601991 - 2¹³ = 8593799 is a prime.

8601991 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8601997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4300995 + 4300996.

It is an arithmetic number, because the mean of its divisors is an integer number (4300996).

Almost surely, 2^8601991 is an apocalyptic number.

8601991 is a deficient number, since it is larger than the sum of its proper divisors (1).

8601991 is an equidigital number, since it uses as much as digits as its factorization.

8601991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 34.

The square root of 8601991 is about 2932.9151027604. The cubic root of 8601991 is about 204.8957709297.

The spelling of 8601991 in words is "eight million, six hundred one thousand, nine hundred ninety-one".