491984639 has 8 divisors (see below), whose sum is σ = 493957440. Its totient is φ = 490016800.

The previous prime is 491984627. The next prime is 491984653. The reversal of 491984639 is 936489194.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 491984639 - 2²⁰ = 490936063 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491984659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 463169 + ... + 464229.

It is an arithmetic number, because the mean of its divisors is an integer number (61744680).

Almost surely, 2^491984639 is an apocalyptic number.

491984639 is a deficient number, since it is larger than the sum of its proper divisors (1972801).

491984639 is a wasteful number, since it uses less digits than its factorization.

491984639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2481.

The product of its digits is 1679616, while the sum is 53.

The square root of 491984639 is about 22180.7267464346. The cubic root of 491984639 is about 789.4364613172.

The spelling of 491984639 in words is "four hundred ninety-one million, nine hundred eighty-four thousand, six hundred thirty-nine".