491258188566 has 24 divisors (see below), whose sum is σ = 1070339077080. Its totient is φ = 162837908736.

The previous prime is 491258188559. The next prime is 491258188567. The reversal of 491258188566 is 665881852194.

491258188566 is a `hidden beast` number, since 4 + 9 + 1 + 2 + 58 + 18 + 8 + 566 = 666.

It is a super-2 number, since 2×491258188566² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491258188567) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 76231755 + ... + 76238198.

It is an arithmetic number, because the mean of its divisors is an integer number (44597461545).

Almost surely, 2^491258188566 is an apocalyptic number.

491258188566 is an abundant number, since it is smaller than the sum of its proper divisors (579080888514).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

491258188566 is a wasteful number, since it uses less digits than its factorization.

491258188566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152470140 (or 152470137 counting only the distinct ones).

The product of its digits is 33177600, while the sum is 63.

The spelling of 491258188566 in words is "four hundred ninety-one billion, two hundred fifty-eight million, one hundred eighty-eight thousand, five hundred sixty-six".