491544913861 has 4 divisors (see below), whose sum is σ = 500819346252. Its totient is φ = 482270481472.

The previous prime is 491544913829. The next prime is 491544913897. The reversal of 491544913861 is 168319445194.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 318130968961 + 173413944900 = 564031^2 + 416430^2 .

It is a cyclic number.

It is not a de Polignac number, because 491544913861 - 2⁵ = 491544913829 is a prime.

It is a super-3 number, since 3×491544913861³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491544913261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4637216116 + ... + 4637216221.

It is an arithmetic number, because the mean of its divisors is an integer number (125204836563).

Almost surely, 2^491544913861 is an apocalyptic number.

It is an amenable number.

491544913861 is a deficient number, since it is larger than the sum of its proper divisors (9274432391).

491544913861 is an equidigital number, since it uses as much as digits as its factorization.

491544913861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9274432390.

The product of its digits is 3732480, while the sum is 55.

The spelling of 491544913861 in words is "four hundred ninety-one billion, five hundred forty-four million, nine hundred thirteen thousand, eight hundred sixty-one".