491290891 has 16 divisors (see below), whose sum is σ = 610029504. Its totient is φ = 385265664.

The previous prime is 491290853. The next prime is 491290897. The reversal of 491290891 is 198092194.

It is a happy number.

It is not a de Polignac number, because 491290891 - 2¹⁵ = 491258123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (491290897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13606 + ... + 34171.

It is an arithmetic number, because the mean of its divisors is an integer number (38126844).

Almost surely, 2^491290891 is an apocalyptic number.

491290891 is a deficient number, since it is larger than the sum of its proper divisors (118738613).

491290891 is a wasteful number, since it uses less digits than its factorization.

491290891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47910.

The product of its (nonzero) digits is 46656, while the sum is 43.

The square root of 491290891 is about 22165.0826977929. The cubic root of 491290891 is about 789.0652250713.

The spelling of 491290891 in words is "four hundred ninety-one million, two hundred ninety thousand, eight hundred ninety-one".