66400100 has 54 divisors (see below), whose sum is σ = 156064230. Its totient is φ = 24510720.

The previous prime is 66400099. The next prime is 66400151. The reversal of 66400100 is 100466.

It can be written as a sum of positive squares in 9 ways, for example, as 54051904 + 12348196 = 7352^2 + 3514^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 14936 + ... + 18864.

Almost surely, 2^66400100 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66400100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78032115).

66400100 is an abundant number, since it is smaller than the sum of its proper divisors (89664130).

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

66400100 is a wasteful number, since it uses less digits than its factorization.

66400100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3969 (or 3949 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 66400100 is about 8148.6256509917. The cubic root of 66400100 is about 404.9389736835.

Adding to 66400100 its reverse (100466), we get a palindrome (66500566).

The spelling of 66400100 in words is "sixty-six million, four hundred thousand, one hundred".