66404420 has 48 divisors (see below), whose sum is σ = 145974528. Its totient is φ = 25347840.

The previous prime is 66404419. The next prime is 66404423. The reversal of 66404420 is 2440466.

It is a self number, because there is not a number n which added to its sum of digits gives 66404420.

It is not an unprimeable number, because it can be changed into a prime (66404423) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 37679 + ... + 39401.

It is an arithmetic number, because the mean of its divisors is an integer number (3041136).

Almost surely, 2^66404420 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66404420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72987264).

66404420 is an abundant number, since it is smaller than the sum of its proper divisors (79570108).

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

66404420 is a wasteful number, since it uses less digits than its factorization.

66404420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1820 (or 1818 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 26.

The square root of 66404420 is about 8148.8907220554. The cubic root of 66404420 is about 404.9477552889.

Adding to 66404420 its reverse (2440466), we get a palindrome (68844886).

The spelling of 66404420 in words is "sixty-six million, four hundred four thousand, four hundred twenty".