491439761 has 4 divisors (see below), whose sum is σ = 491580132. Its totient is φ = 491299392.

The previous prime is 491439737. The next prime is 491439779. The reversal of 491439761 is 167934194.

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

It can be written as a sum of positive squares in 2 ways, for example, as 45427600 + 446012161 = 6740^2 + 21119^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491439761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491439701) 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, 64796 + ... + 71981.

It is an arithmetic number, because the mean of its divisors is an integer number (122895033).

Almost surely, 2^491439761 is an apocalyptic number.

It is an amenable number.

491439761 is a deficient number, since it is larger than the sum of its proper divisors (140371).

491439761 is a wasteful number, since it uses less digits than its factorization.

491439761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140370.

The product of its digits is 163296, while the sum is 44.

The square root of 491439761 is about 22168.4406533252. The cubic root of 491439761 is about 789.1449173535.

The spelling of 491439761 in words is "four hundred ninety-one million, four hundred thirty-nine thousand, seven hundred sixty-one".