66780100 has 18 divisors (see below), whose sum is σ = 144913034. Its totient is φ = 26712000.

The previous prime is 66780071. The next prime is 66780101. The reversal of 66780100 is 108766.

It can be written as a sum of positive squares in 3 ways, for example, as 715716 + 66064384 = 846^2 + 8128^2 .

It is not an unprimeable number, because it can be changed into a prime (66780101) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 333801 + ... + 334000.

Almost surely, 2^66780100 is an apocalyptic number.

It is an amenable number.

66780100 is an abundant number, since it is smaller than the sum of its proper divisors (78132934).

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

66780100 is a wasteful number, since it uses less digits than its factorization.

66780100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 667815 (or 667808 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 66780100 is about 8171.9092016493. The cubic root of 66780100 is about 405.7099775428.

Adding to 66780100 its reverse (108766), we get a palindrome (66888866).

The spelling of 66780100 in words is "sixty-six million, seven hundred eighty thousand, one hundred".