491801856 has 288 divisors, whose sum is σ = 1670258688. Its totient is φ = 124968960.

The previous prime is 491801851. The next prime is 491801867. The reversal of 491801856 is 658108194.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491801851) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2166415 + ... + 2166641.

Almost surely, 2^491801856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 491801856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (835129344).

491801856 is an abundant number, since it is smaller than the sum of its proper divisors (1178456832).

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

491801856 is a wasteful number, since it uses less digits than its factorization.

491801856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297 (or 283 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 42.

The square root of 491801856 is about 22176.6060523246. The cubic root of 491801856 is about 789.3386849325.

The spelling of 491801856 in words is "four hundred ninety-one million, eight hundred one thousand, eight hundred fifty-six".