851491 has 2 divisors, whose sum is σ = 851492. Its totient is φ = 851490.

The previous prime is 851471. The next prime is 851507. The reversal of 851491 is 194158.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 851491 - 2⁷ = 851363 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (851401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 425745 + 425746.

It is an arithmetic number, because the mean of its divisors is an integer number (425746).

2⁸⁵¹⁴⁹¹ is an apocalyptic number.

851491 is a deficient number, since it is larger than the sum of its proper divisors (1).

851491 is an equidigital number, since it uses as much as digits as its factorization.

851491 is an evil number, because the sum of its binary digits is even.

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

The square root of 851491 is about 922.7626997230. The cubic root of 851491 is about 94.7821786959.

The spelling of 851491 in words is "eight hundred fifty-one thousand, four hundred ninety-one".