491851 has 2 divisors, whose sum is σ = 491852. Its totient is φ = 491850.

The previous prime is 491837. The next prime is 491857. The reversal of 491851 is 158194.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 491851 - 2⁵ = 491819 is a prime.

It is not a weakly prime, because it can be changed into another prime (491857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245925 + 245926.

It is an arithmetic number, because the mean of its divisors is an integer number (245926).

2⁴⁹¹⁸⁵¹ is an apocalyptic number.

491851 is a deficient number, since it is larger than the sum of its proper divisors (1).

491851 is an equidigital number, since it uses as much as digits as its factorization.

491851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 28.

The square root of 491851 is about 701.3208965944. The cubic root of 491851 is about 78.9364975987.

The spelling of 491851 in words is "four hundred ninety-one thousand, eight hundred fifty-one".