66221020 has 12 divisors (see below), whose sum is σ = 139064184. Its totient is φ = 26488400.

The previous prime is 66221003. The next prime is 66221021. The reversal of 66221020 is 2012266.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66221021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1655506 + ... + 1655545.

It is an arithmetic number, because the mean of its divisors is an integer number (11588682).

Almost surely, 2^66221020 is an apocalyptic number.

It is an amenable number.

66221020 is an abundant number, since it is smaller than the sum of its proper divisors (72843164).

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

66221020 is a wasteful number, since it uses less digits than its factorization.

66221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3311060 (or 3311058 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 66221020 is about 8137.6298760757. The cubic root of 66221020 is about 404.5746079613.

Adding to 66221020 its reverse (2012266), we get a palindrome (68233286).

The spelling of 66221020 in words is "sixty-six million, two hundred twenty-one thousand, twenty".