66180816 has 60 divisors (see below), whose sum is σ = 199467268. Its totient is φ = 20362752.

The previous prime is 66180787. The next prime is 66180817. The reversal of 66180816 is 61808166.

It can be written as a sum of positive squares in 2 ways, for example, as 44836416 + 21344400 = 6696^2 + 4620^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66180817) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15805 + ... + 19548.

Almost surely, 2^66180816 is an apocalyptic number.

It is an amenable number.

66180816 is an abundant number, since it is smaller than the sum of its proper divisors (133286452).

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

66180816 is a wasteful number, since it uses less digits than its factorization.

66180816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35380 (or 35371 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 66180816 is about 8135.1592485950. The cubic root of 66180816 is about 404.4927164896.

The spelling of 66180816 in words is "sixty-six million, one hundred eighty thousand, eight hundred sixteen".