491573381 has 8 divisors (see below), whose sum is σ = 531662040. Its totient is φ = 451809792.

The previous prime is 491573359. The next prime is 491573389. The reversal of 491573381 is 183375194.

It can be written as a sum of positive squares in 4 ways, for example, as 6076225 + 485497156 = 2465^2 + 22034^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491573381 is a prime.

It is a super-2 number, since 2×491573381² = 483288777815542322, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491573389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78116 + ... + 84173.

It is an arithmetic number, because the mean of its divisors is an integer number (66457755).

Almost surely, 2^491573381 is an apocalyptic number.

It is an amenable number.

491573381 is a deficient number, since it is larger than the sum of its proper divisors (40088659).

491573381 is a wasteful number, since it uses less digits than its factorization.

491573381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162535.

The product of its digits is 90720, while the sum is 41.

The square root of 491573381 is about 22171.4541922716. The cubic root of 491573381 is about 789.2164323841.

The spelling of 491573381 in words is "four hundred ninety-one million, five hundred seventy-three thousand, three hundred eighty-one".