66573979920 has 1280 divisors, whose sum is σ = 292267008000. Its totient is φ = 13586227200.

The previous prime is 66573979907. The next prime is 66573979921. The reversal of 66573979920 is 2997937566.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (66573979921) 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 255 ways as a sum of consecutive naturals, for example, 508198255 + ... + 508198385.

It is an arithmetic number, because the mean of its divisors is an integer number (228333600).

Almost surely, 2^66573979920 is an apocalyptic number.

66573979920 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 66573979920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (146133504000).

66573979920 is an abundant number, since it is smaller than the sum of its proper divisors (225693028080).

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

66573979920 is a wasteful number, since it uses less digits than its factorization.

66573979920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269 (or 257 counting only the distinct ones).

The product of its (nonzero) digits is 38578680, while the sum is 63.

The spelling of 66573979920 in words is "sixty-six billion, five hundred seventy-three million, nine hundred seventy-nine thousand, nine hundred twenty".