491064561 has 12 divisors (see below), whose sum is σ = 763878388. Its totient is φ = 302193504.

The previous prime is 491064527. The next prime is 491064593. The reversal of 491064561 is 165460194.

491064561 is a `hidden beast` number, since 4 + 9 + 1 + 0 + 645 + 6 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 45643536 + 445421025 = 6756^2 + 21105^2 .

It is not a de Polignac number, because 491064561 - 2⁷ = 491064433 is a prime.

It is a super-2 number, since 2×491064561² = 482288806140245442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (491064061) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2098450 + ... + 2098683.

Almost surely, 2^491064561 is an apocalyptic number.

It is an amenable number.

491064561 is a deficient number, since it is larger than the sum of its proper divisors (272813827).

491064561 is a wasteful number, since it uses less digits than its factorization.

491064561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4197152 (or 4197149 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 491064561 is about 22159.9765568468. The cubic root of 491064561 is about 788.9440364726.

The spelling of 491064561 in words is "four hundred ninety-one million, sixty-four thousand, five hundred sixty-one".