491947787 has 4 divisors (see below), whose sum is σ = 495249600. Its totient is φ = 488645976.

The previous prime is 491947777. The next prime is 491947789. The reversal of 491947787 is 787749194.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 491947787 - 2⁸ = 491947531 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491947789) 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, 1650683 + ... + 1650980.

It is an arithmetic number, because the mean of its divisors is an integer number (123812400).

Almost surely, 2^491947787 is an apocalyptic number.

491947787 is a deficient number, since it is larger than the sum of its proper divisors (3301813).

491947787 is a wasteful number, since it uses less digits than its factorization.

491947787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3301812.

The product of its digits is 3556224, while the sum is 56.

The square root of 491947787 is about 22179.8960096751. The cubic root of 491947787 is about 789.4167499708.

The spelling of 491947787 in words is "four hundred ninety-one million, nine hundred forty-seven thousand, seven hundred eighty-seven".