491179921 has 8 divisors (see below), whose sum is σ = 505509440. Its totient is φ = 476905968.

The previous prime is 491179891. The next prime is 491179933. The reversal of 491179921 is 129971194.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491179921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491179121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4390 + ... + 31648.

It is an arithmetic number, because the mean of its divisors is an integer number (63188680).

Almost surely, 2^491179921 is an apocalyptic number.

It is an amenable number.

491179921 is a deficient number, since it is larger than the sum of its proper divisors (14329519).

491179921 is a wasteful number, since it uses less digits than its factorization.

491179921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27783.

The product of its digits is 40824, while the sum is 43.

The square root of 491179921 is about 22162.5792948384. The cubic root of 491179921 is about 789.0058107384.

The spelling of 491179921 in words is "four hundred ninety-one million, one hundred seventy-nine thousand, nine hundred twenty-one".