491211864 has 448 divisors, whose sum is σ = 1762790400. Its totient is φ = 125971200.

The previous prime is 491211839. The next prime is 491211881. The reversal of 491211864 is 468112194.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 15845529 + ... + 15845559.

It is an arithmetic number, because the mean of its divisors is an integer number (3934800).

Almost surely, 2^491211864 is an apocalyptic number.

491211864 is a gapful number since it is divisible by the number (44) 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 491211864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (881395200).

491211864 is an abundant number, since it is smaller than the sum of its proper divisors (1271578536).

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

491211864 is a wasteful number, since it uses less digits than its factorization.

491211864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 79 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 491211864 is about 22163.2999348021. The cubic root of 491211864 is about 789.0229142241.

The spelling of 491211864 in words is "four hundred ninety-one million, two hundred eleven thousand, eight hundred sixty-four".