491975801863 has 48 divisors (see below), whose sum is σ = 620560486560. Its totient is φ = 386586950400.

The previous prime is 491975801827. The next prime is 491975801879. The reversal of 491975801863 is 368108579194.

It is a de Polignac number, because none of the positive numbers 2^k-491975801863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491975801813) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 61408528 + ... + 61416538.

It is an arithmetic number, because the mean of its divisors is an integer number (12928343470).

Almost surely, 2^491975801863 is an apocalyptic number.

491975801863 is a deficient number, since it is larger than the sum of its proper divisors (128584684697).

491975801863 is a wasteful number, since it uses less digits than its factorization.

491975801863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8688 (or 8681 counting only the distinct ones).

The product of its (nonzero) digits is 13063680, while the sum is 61.

The spelling of 491975801863 in words is "four hundred ninety-one billion, nine hundred seventy-five million, eight hundred one thousand, eight hundred sixty-three".