491778194987507 has 2 divisors, whose sum is σ = 491778194987508. Its totient is φ = 491778194987506.

The previous prime is 491778194987477. The next prime is 491778194987557. The reversal of 491778194987507 is 705789491877194.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 491778194987507 - 2¹⁶ = 491778194921971 is a prime.

It is not a weakly prime, because it can be changed into another prime (491778194987557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245889097493753 + 245889097493754.

It is an arithmetic number, because the mean of its divisors is an integer number (245889097493754).

Almost surely, 2^{491778194987507} is an apocalyptic number.

491778194987507 is a deficient number, since it is larger than the sum of its proper divisors (1).

491778194987507 is an equidigital number, since it uses as much as digits as its factorization.

491778194987507 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8961684480, while the sum is 86.

The spelling of 491778194987507 in words is "four hundred ninety-one trillion, seven hundred seventy-eight billion, one hundred ninety-four million, nine hundred eighty-seven thousand, five hundred seven".