581121864 has 192 divisors, whose sum is σ = 1750170240. Its totient is φ = 180195840.

The previous prime is 581121833. The next prime is 581121899. The reversal of 581121864 is 468121185.

581121864 is a `hidden beast` number, since 581 + 1 + 2 + 18 + 64 = 666.

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

It is a zygodrome in base 3.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1833034 + ... + 1833350.

It is an arithmetic number, because the mean of its divisors is an integer number (9115470).

Almost surely, 2^581121864 is an apocalyptic number.

581121864 is a gapful number since it is divisible by the number (54) 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 581121864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (875085120).

581121864 is an abundant number, since it is smaller than the sum of its proper divisors (1169048376).

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

581121864 is a wasteful number, since it uses less digits than its factorization.

581121864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402 (or 386 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 581121864 is about 24106.4693391629. The cubic root of 581121864 is about 834.4924373016.

The spelling of 581121864 in words is "five hundred eighty-one million, one hundred twenty-one thousand, eight hundred sixty-four".