66838920 has 128 divisors (see below), whose sum is σ = 213200640. Its totient is φ = 16727040.

The previous prime is 66838913. The next prime is 66838921. The reversal of 66838920 is 2983866.

It is not an unprimeable number, because it can be changed into a prime (66838921) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 168162 + ... + 168558.

It is an arithmetic number, because the mean of its divisors is an integer number (1665630).

Almost surely, 2^66838920 is an apocalyptic number.

66838920 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 66838920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106600320).

66838920 is an abundant number, since it is smaller than the sum of its proper divisors (146361720).

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

66838920 is a wasteful number, since it uses less digits than its factorization.

66838920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495 (or 491 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 66838920 is about 8175.5073237078. The cubic root of 66838920 is about 405.8290592147.

The spelling of 66838920 in words is "sixty-six million, eight hundred thirty-eight thousand, nine hundred twenty".