8387491691 has 2 divisors, whose sum is σ = 8387491692. Its totient is φ = 8387491690.

The previous prime is 8387491661. The next prime is 8387491747. The reversal of 8387491691 is 1961947838.

It is an a-pointer prime, because the next prime (8387491747) can be obtained adding 8387491691 to its sum of digits (56).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 8387491691 - 2²⁶ = 8320382827 is a prime.

It is not a weakly prime, because it can be changed into another prime (8387491661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4193745845 + 4193745846.

It is an arithmetic number, because the mean of its divisors is an integer number (4193745846).

Almost surely, 2^8387491691 is an apocalyptic number.

8387491691 is a deficient number, since it is larger than the sum of its proper divisors (1).

8387491691 is an equidigital number, since it uses as much as digits as its factorization.

8387491691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2612736, while the sum is 56.

The square root of 8387491691 is about 91583.2500569837. The cubic root of 8387491691 is about 2031.7832124103.

The spelling of 8387491691 in words is "eight billion, three hundred eighty-seven million, four hundred ninety-one thousand, six hundred ninety-one".