491994431 has 4 divisors (see below), whose sum is σ = 492260664. Its totient is φ = 491728200.

The previous prime is 491994427. The next prime is 491994443. The reversal of 491994431 is 134499194.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 491994431 - 2² = 491994427 is a prime.

It is a super-2 number, since 2×491994431² = 484117040270027522, which contains 22 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 (491994401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 130325 + ... + 134046.

It is an arithmetic number, because the mean of its divisors is an integer number (123065166).

Almost surely, 2^491994431 is an apocalyptic number.

491994431 is a deficient number, since it is larger than the sum of its proper divisors (266233).

491994431 is a wasteful number, since it uses less digits than its factorization.

491994431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266232.

The product of its digits is 139968, while the sum is 44.

The square root of 491994431 is about 22180.9474775087. The cubic root of 491994431 is about 789.4416986830.

The spelling of 491994431 in words is "four hundred ninety-one million, nine hundred ninety-four thousand, four hundred thirty-one".