491648640 has 256 divisors, whose sum is σ = 1810149120. Its totient is φ = 111181824.

The previous prime is 491648639. The next prime is 491648657. The reversal of 491648640 is 46846194.

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

It is a junction number, because it is equal to n+sod(n) for n = 491648592 and 491648601.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2109964 + ... + 2110196.

It is an arithmetic number, because the mean of its divisors is an integer number (7070895).

Almost surely, 2^491648640 is an apocalyptic number.

491648640 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 491648640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (905074560).

491648640 is an abundant number, since it is smaller than the sum of its proper divisors (1318500480).

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

491648640 is a wasteful number, since it uses less digits than its factorization.

491648640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419 (or 407 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 42.

The square root of 491648640 is about 22173.1513321855. The cubic root of 491648640 is about 789.2567062007.

The spelling of 491648640 in words is "four hundred ninety-one million, six hundred forty-eight thousand, six hundred forty".