491487851 has 4 divisors (see below), whose sum is σ = 512856912. Its totient is φ = 470118792.

The previous prime is 491487823. The next prime is 491487949. The reversal of 491487851 is 158784194.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 158784194 = 2 ⋅79392097.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491487851 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 491487796 and 491487805.

It is not an unprimeable number, because it can be changed into a prime (491487151) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10684496 + ... + 10684541.

It is an arithmetic number, because the mean of its divisors is an integer number (128214228).

Almost surely, 2^491487851 is an apocalyptic number.

491487851 is a deficient number, since it is larger than the sum of its proper divisors (21369061).

491487851 is a wasteful number, since it uses less digits than its factorization.

491487851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21369060.

The product of its digits is 322560, while the sum is 47.

The square root of 491487851 is about 22169.5252768299. The cubic root of 491487851 is about 789.1706571927.

The spelling of 491487851 in words is "four hundred ninety-one million, four hundred eighty-seven thousand, eight hundred fifty-one".