66390589440 has 672 divisors, whose sum is σ = 273804034560. Its totient is φ = 14948499456.

The previous prime is 66390589423. The next prime is 66390589453. The reversal of 66390589440 is 4498509366.

66390589440 is a `hidden beast` number, since 6 + 63 + 90 + 58 + 9 + 440 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nialpdrome in base 16.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 990904287 + ... + 990904353.

It is an arithmetic number, because the mean of its divisors is an integer number (407446480).

Almost surely, 2^66390589440 is an apocalyptic number.

66390589440 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 66390589440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136902017280).

66390589440 is an abundant number, since it is smaller than the sum of its proper divisors (207413445120).

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

66390589440 is an frugal number, since it uses more digits than its factorization.

66390589440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128 (or 84 counting only the distinct ones).

The product of its (nonzero) digits is 5598720, while the sum is 54.

The spelling of 66390589440 in words is "sixty-six billion, three hundred ninety million, five hundred eighty-nine thousand, four hundred forty".