491481389257 has 2 divisors, whose sum is σ = 491481389258. Its totient is φ = 491481389256.

The previous prime is 491481389251. The next prime is 491481389297. The reversal of 491481389257 is 752983184194.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 490834755216 + 646634041 = 700596^2 + 25429^2 .

It is a cyclic number.

It is not a de Polignac number, because 491481389257 - 2³ = 491481389249 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 491481389195 and 491481389204.

It is not a weakly prime, because it can be changed into another prime (491481389251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245740694628 + 245740694629.

It is an arithmetic number, because the mean of its divisors is an integer number (245740694629).

Almost surely, 2^491481389257 is an apocalyptic number.

It is an amenable number.

491481389257 is a deficient number, since it is larger than the sum of its proper divisors (1).

491481389257 is an equidigital number, since it uses as much as digits as its factorization.

491481389257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17418240, while the sum is 61.

The spelling of 491481389257 in words is "four hundred ninety-one billion, four hundred eighty-one million, three hundred eighty-nine thousand, two hundred fifty-seven".