491812881 has 8 divisors (see below), whose sum is σ = 749429184. Its totient is φ = 281035920.

The previous prime is 491812879. The next prime is 491812939. The reversal of 491812881 is 188218194.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 491812881 - 2¹ = 491812879 is a prime.

It is a super-2 number, since 2×491812881² = 483759819835040322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (491812081) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11709810 + ... + 11709851.

It is an arithmetic number, because the mean of its divisors is an integer number (93678648).

Almost surely, 2^491812881 is an apocalyptic number.

It is an amenable number.

491812881 is a deficient number, since it is larger than the sum of its proper divisors (257616303).

491812881 is a wasteful number, since it uses less digits than its factorization.

491812881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23419671.

The product of its digits is 36864, while the sum is 42.

The square root of 491812881 is about 22176.8546236837. The cubic root of 491812881 is about 789.3445832388.

The spelling of 491812881 in words is "four hundred ninety-one million, eight hundred twelve thousand, eight hundred eighty-one".