66128200720 has 40 divisors (see below), whose sum is σ = 162792073944. Its totient is φ = 24895322112.

The previous prime is 66128200681. The next prime is 66128200741. The reversal of 66128200720 is 2700282166.

It can be written as a sum of positive squares in 4 ways, for example, as 9689646096 + 56438554624 = 98436^2 + 237568^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (34).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24310479 + ... + 24313198.

Almost surely, 2^66128200720 is an apocalyptic number.

It is an amenable number.

66128200720 is an abundant number, since it is smaller than the sum of its proper divisors (96663873224).

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

66128200720 is a wasteful number, since it uses less digits than its factorization.

66128200720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48623707 (or 48623701 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 34.

Adding to 66128200720 its reverse (2700282166), we get a palindrome (68828482886).

The spelling of 66128200720 in words is "sixty-six billion, one hundred twenty-eight million, two hundred thousand, seven hundred twenty".