66826321920 has 480 divisors, whose sum is σ = 241175605440. Its totient is φ = 17772576768.

The previous prime is 66826321901. The next prime is 66826321927. The reversal of 66826321920 is 2912362866.

66826321920 is a `hidden beast` number, since 6 + 6 + 8 + 2 + 632 + 1 + 9 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (66826321927) 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, 179158854 + ... + 179159226.

It is an arithmetic number, because the mean of its divisors is an integer number (502449178).

Almost surely, 2^66826321920 is an apocalyptic number.

66826321920 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 66826321920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120587802720).

66826321920 is an abundant number, since it is smaller than the sum of its proper divisors (174349283520).

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

66826321920 is an frugal number, since it uses more digits than its factorization.

66826321920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427 (or 383 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The spelling of 66826321920 in words is "sixty-six billion, eight hundred twenty-six million, three hundred twenty-one thousand, nine hundred twenty".