491978329 has 4 divisors (see below), whose sum is σ = 493181620. Its totient is φ = 490775040.

The previous prime is 491978327. The next prime is 491978369. The reversal of 491978329 is 923879194.

It is a happy number.

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 442134729 + 49843600 = 21027^2 + 7060^2 .

It is a cyclic number.

It is not a de Polignac number, because 491978329 - 2¹ = 491978327 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491978327) 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, 601032 + ... + 601849.

It is an arithmetic number, because the mean of its divisors is an integer number (123295405).

Almost surely, 2^491978329 is an apocalyptic number.

It is an amenable number.

491978329 is a deficient number, since it is larger than the sum of its proper divisors (1203291).

491978329 is a wasteful number, since it uses less digits than its factorization.

491978329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1203290.

The product of its digits is 979776, while the sum is 52.

The square root of 491978329 is about 22180.5845053732. The cubic root of 491978329 is about 789.4330863030.

The spelling of 491978329 in words is "four hundred ninety-one million, nine hundred seventy-eight thousand, three hundred twenty-nine".