64581840 has 160 divisors (see below), whose sum is σ = 230342400. Its totient is φ = 16611840.

The previous prime is 64581833. The next prime is 64581841. The reversal of 64581840 is 4818546.

64581840 is a `hidden beast` number, since 645 + 8 + 1 + 8 + 4 + 0 = 666.

64581840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a junction number, because it is equal to n+sod(n) for n = 64581795 and 64581804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64581841) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 62125 + ... + 63155.

It is an arithmetic number, because the mean of its divisors is an integer number (1439640).

Almost surely, 2^64581840 is an apocalyptic number.

64581840 is a gapful number since it is divisible by the number (60) 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 64581840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115171200).

64581840 is an abundant number, since it is smaller than the sum of its proper divisors (165760560).

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

64581840 is a wasteful number, since it uses less digits than its factorization.

64581840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1082 (or 1070 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The square root of 64581840 is about 8036.2827227519. The cubic root of 64581840 is about 401.2085117380.

The spelling of 64581840 in words is "sixty-four million, five hundred eighty-one thousand, eight hundred forty".