491773908561 has 32 divisors (see below), whose sum is σ = 717023475840. Its totient is φ = 297968799744.

The previous prime is 491773908553. The next prime is 491773908607. The reversal of 491773908561 is 165809377194.

It is not a de Polignac number, because 491773908561 - 2³ = 491773908553 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 491773908495 and 491773908504.

It is not an unprimeable number, because it can be changed into a prime (491773908551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5476735 + ... + 5565803.

It is an arithmetic number, because the mean of its divisors is an integer number (22406983620).

Almost surely, 2^491773908561 is an apocalyptic number.

It is an amenable number.

491773908561 is a deficient number, since it is larger than the sum of its proper divisors (225249567279).

491773908561 is a wasteful number, since it uses less digits than its factorization.

491773908561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91265.

The product of its (nonzero) digits is 11430720, while the sum is 60.

The spelling of 491773908561 in words is "four hundred ninety-one billion, seven hundred seventy-three million, nine hundred eight thousand, five hundred sixty-one".