491961563 has 2 divisors, whose sum is σ = 491961564. Its totient is φ = 491961562.

The previous prime is 491961553. The next prime is 491961577. The reversal of 491961563 is 365169194.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 491961563 - 2⁶ = 491961499 is a prime.

It is not a weakly prime, because it can be changed into another prime (491961553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245980781 + 245980782.

It is an arithmetic number, because the mean of its divisors is an integer number (245980782).

Almost surely, 2^491961563 is an apocalyptic number.

491961563 is a deficient number, since it is larger than the sum of its proper divisors (1).

491961563 is an equidigital number, since it uses as much as digits as its factorization.

491961563 is an evil number, because the sum of its binary digits is even.

The product of its digits is 174960, while the sum is 44.

The square root of 491961563 is about 22180.2065590021. The cubic root of 491961563 is about 789.4241185737.

The spelling of 491961563 in words is "four hundred ninety-one million, nine hundred sixty-one thousand, five hundred sixty-three".