66256720 has 20 divisors (see below), whose sum is σ = 154047060. Its totient is φ = 26502656.

The previous prime is 66256711. The next prime is 66256727. The reversal of 66256720 is 2765266.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 6843456 + 59413264 = 2616^2 + 7708^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66256727) 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, 414025 + ... + 414184.

It is an arithmetic number, because the mean of its divisors is an integer number (7702353).

Almost surely, 2^66256720 is an apocalyptic number.

It is an amenable number.

66256720 is an abundant number, since it is smaller than the sum of its proper divisors (87790340).

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

66256720 is a wasteful number, since it uses less digits than its factorization.

66256720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 828222 (or 828216 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 34.

The square root of 66256720 is about 8139.8230939008. The cubic root of 66256720 is about 404.6472974628.

The spelling of 66256720 in words is "sixty-six million, two hundred fifty-six thousand, seven hundred twenty".