66661240033872 has 240 divisors, whose sum is σ = 203811631934976. Its totient is φ = 20171327616000.

The previous prime is 66661240033831. The next prime is 66661240033877. The reversal of 66661240033872 is 27833004216666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66661240033877) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4302660558 + ... + 4302676050.

Almost surely, 2^{66661240033872} 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 66661240033872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101905815967488).

66661240033872 is an abundant number, since it is smaller than the sum of its proper divisors (137150391901104).

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

66661240033872 is a wasteful number, since it uses less digits than its factorization.

66661240033872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19250 (or 19241 counting only the distinct ones).

The product of its (nonzero) digits is 10450944, while the sum is 54.

The spelling of 66661240033872 in words is "sixty-six trillion, six hundred sixty-one billion, two hundred forty million, thirty-three thousand, eight hundred seventy-two".