491819261 has 2 divisors, whose sum is σ = 491819262. Its totient is φ = 491819260.

The previous prime is 491819249. The next prime is 491819353. The reversal of 491819261 is 162918194.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 408444100 + 83375161 = 20210^2 + 9131^2 .

It is a cyclic number.

It is not a de Polignac number, because 491819261 - 2¹⁰ = 491818237 is a prime.

It is a super-2 number, since 2×491819261² = 483772370981172242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (491819561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245909630 + 245909631.

It is an arithmetic number, because the mean of its divisors is an integer number (245909631).

Almost surely, 2^491819261 is an apocalyptic number.

It is an amenable number.

491819261 is a deficient number, since it is larger than the sum of its proper divisors (1).

491819261 is an equidigital number, since it uses as much as digits as its factorization.

491819261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 41.

The square root of 491819261 is about 22176.9984668800. The cubic root of 491819261 is about 789.3479964588.

The spelling of 491819261 in words is "four hundred ninety-one million, eight hundred nineteen thousand, two hundred sixty-one".