491974561 has 16 divisors (see below), whose sum is σ = 536171328. Its totient is φ = 448718400.

The previous prime is 491974559. The next prime is 491974573. The reversal of 491974561 is 165479194.

It is not a de Polignac number, because 491974561 - 2¹ = 491974559 is a prime.

It is a super-2 number, since 2×491974561² = 484077937342285442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491971561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 522351 + ... + 523291.

It is an arithmetic number, because the mean of its divisors is an integer number (33510708).

Almost surely, 2^491974561 is an apocalyptic number.

It is an amenable number.

491974561 is a deficient number, since it is larger than the sum of its proper divisors (44196767).

491974561 is a wasteful number, since it uses less digits than its factorization.

491974561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1392.

The product of its digits is 272160, while the sum is 46.

The square root of 491974561 is about 22180.4995660603. The cubic root of 491974561 is about 789.4310709084.

The spelling of 491974561 in words is "four hundred ninety-one million, nine hundred seventy-four thousand, five hundred sixty-one".