491334821 has 2 divisors, whose sum is σ = 491334822. Its totient is φ = 491334820.

The previous prime is 491334793. The next prime is 491334853. The reversal of 491334821 is 128433194.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 475850596 + 15484225 = 21814^2 + 3935^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491334821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (491334871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245667410 + 245667411.

It is an arithmetic number, because the mean of its divisors is an integer number (245667411).

Almost surely, 2^491334821 is an apocalyptic number.

It is an amenable number.

491334821 is a deficient number, since it is larger than the sum of its proper divisors (1).

491334821 is an equidigital number, since it uses as much as digits as its factorization.

491334821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20736, while the sum is 35.

The square root of 491334821 is about 22166.0736487092. The cubic root of 491334821 is about 789.0887431152.

The spelling of 491334821 in words is "four hundred ninety-one million, three hundred thirty-four thousand, eight hundred twenty-one".