491808986387 has 2 divisors, whose sum is σ = 491808986388. Its totient is φ = 491808986386.

The previous prime is 491808986351. The next prime is 491808986401. The reversal of 491808986387 is 783689808194.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 491808986387 - 2⁶ = 491808986323 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 491808986387.

It is not a weakly prime, because it can be changed into another prime (491808986287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245904493193 + 245904493194.

It is an arithmetic number, because the mean of its divisors is an integer number (245904493194).

Almost surely, 2^491808986387 is an apocalyptic number.

491808986387 is a deficient number, since it is larger than the sum of its proper divisors (1).

491808986387 is an equidigital number, since it uses as much as digits as its factorization.

491808986387 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 167215104, while the sum is 71.

The spelling of 491808986387 in words is "four hundred ninety-one billion, eight hundred eight million, nine hundred eighty-six thousand, three hundred eighty-seven".