491996660 has 48 divisors (see below), whose sum is σ = 1129282560. Its totient is φ = 179243520.

The previous prime is 491996651. The next prime is 491996663. The reversal of 491996660 is 66699194.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 491996599 and 491996608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491996663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12800 + ... + 33879.

It is an arithmetic number, because the mean of its divisors is an integer number (23526720).

Almost surely, 2^491996660 is an apocalyptic number.

It is an amenable number.

491996660 is an abundant number, since it is smaller than the sum of its proper divisors (637285900).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

491996660 is a wasteful number, since it uses less digits than its factorization.

491996660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46736 (or 46734 counting only the distinct ones).

The product of its (nonzero) digits is 629856, while the sum is 50.

The square root of 491996660 is about 22180.9977232766. The cubic root of 491996660 is about 789.4428908800.

The spelling of 491996660 in words is "four hundred ninety-one million, nine hundred ninety-six thousand, six hundred sixty".