491794991 has 4 divisors (see below), whose sum is σ = 491839800. Its totient is φ = 491750184.

The previous prime is 491794969. The next prime is 491794997. The reversal of 491794991 is 199497194.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491794991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491794997) 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, 6425 + ... + 32013.

It is an arithmetic number, because the mean of its divisors is an integer number (122959950).

Almost surely, 2^491794991 is an apocalyptic number.

491794991 is a deficient number, since it is larger than the sum of its proper divisors (44809).

491794991 is a wasteful number, since it uses less digits than its factorization.

491794991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44808.

The product of its digits is 734832, while the sum is 53.

The square root of 491794991 is about 22176.4512715628. The cubic root of 491794991 is about 789.3350121557.

The spelling of 491794991 in words is "four hundred ninety-one million, seven hundred ninety-four thousand, nine hundred ninety-one".