66420020 has 24 divisors (see below), whose sum is σ = 147687624. Its totient is φ = 25005056.

The previous prime is 66420007. The next prime is 66420023. The reversal of 66420020 is 2002466.

It can be written as a sum of positive squares in 4 ways, for example, as 550564 + 65869456 = 742^2 + 8116^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 66419974 and 66420001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66420023) 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 7 ways as a sum of consecutive naturals, for example, 97337 + ... + 98016.

It is an arithmetic number, because the mean of its divisors is an integer number (6153651).

Almost surely, 2^66420020 is an apocalyptic number.

It is an amenable number.

66420020 is an abundant number, since it is smaller than the sum of its proper divisors (81267604).

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

66420020 is a wasteful number, since it uses less digits than its factorization.

66420020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195379 (or 195377 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 66420020 is about 8149.8478513405. The cubic root of 66420020 is about 404.9794634712.

Adding to 66420020 its reverse (2002466), we get a palindrome (68422486).

The spelling of 66420020 in words is "sixty-six million, four hundred twenty thousand, twenty".