491751 has 20 divisors (see below), whose sum is σ = 792792. Its totient is φ = 301968.

The previous prime is 491747. The next prime is 491773. The reversal of 491751 is 157194.

It is not a de Polignac number, because 491751 - 2² = 491747 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 2.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 491751.

It is not an unprimeable number, because it can be changed into a prime (491731) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 820 + ... + 1286.

2⁴⁹¹⁷⁵¹ is an apocalyptic number.

491751 is the 351-st decagonal number.

491751 is a deficient number, since it is larger than the sum of its proper divisors (301041).

491751 is a wasteful number, since it uses less digits than its factorization.

491751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492 (or 483 counting only the distinct ones).

The product of its digits is 1260, while the sum is 27.

The square root of 491751 is about 701.2495989304. The cubic root of 491751 is about 78.9311476148.

The spelling of 491751 in words is "four hundred ninety-one thousand, seven hundred fifty-one".