66581420 has 24 divisors (see below), whose sum is σ = 140532000. Its totient is φ = 26497152.

The previous prime is 66581413. The next prime is 66581443. The reversal of 66581420 is 2418566.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4385 + ... + 12344.

It is an arithmetic number, because the mean of its divisors is an integer number (5855500).

Almost surely, 2^66581420 is an apocalyptic number.

It is an amenable number.

66581420 is an abundant number, since it is smaller than the sum of its proper divisors (73950580).

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

66581420 is a wasteful number, since it uses less digits than its factorization.

66581420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16937 (or 16935 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 66581420 is about 8159.7438685292. The cubic root of 66581420 is about 405.3072301716.

Adding to 66581420 its reverse (2418566), we get a palindrome (68999986).

The spelling of 66581420 in words is "sixty-six million, five hundred eighty-one thousand, four hundred twenty".