491868889 has 4 divisors (see below), whose sum is σ = 496738980. Its totient is φ = 486998800.

The previous prime is 491868877. The next prime is 491868893. The reversal of 491868889 is 988868194.

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 387420489 + 104448400 = 19683^2 + 10220^2 .

It is a cyclic number.

It is not a de Polignac number, because 491868889 - 2⁵ = 491868857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491868809) 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, 2434894 + ... + 2435095.

It is an arithmetic number, because the mean of its divisors is an integer number (124184745).

Almost surely, 2^491868889 is an apocalyptic number.

It is an amenable number.

491868889 is a deficient number, since it is larger than the sum of its proper divisors (4870091).

491868889 is a wasteful number, since it uses less digits than its factorization.

491868889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4870090.

The product of its digits is 7962624, while the sum is 61.

The square root of 491868889 is about 22178.1173457081. The cubic root of 491868889 is about 789.3745458086.

The spelling of 491868889 in words is "four hundred ninety-one million, eight hundred sixty-eight thousand, eight hundred eighty-nine".