66779681472 has 672 divisors, whose sum is σ = 237782039040. Its totient is φ = 18184642560.

The previous prime is 66779681471. The next prime is 66779681477. The reversal of 66779681472 is 27418697766.

66779681472 is a `hidden beast` number, since 6 + 6 + 77 + 96 + 8 + 1 + 472 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (66779681471) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 237649972 + ... + 237650252.

It is an arithmetic number, because the mean of its divisors is an integer number (353842320).

Almost surely, 2^66779681472 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 66779681472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118891019520).

66779681472 is an abundant number, since it is smaller than the sum of its proper divisors (171002357568).

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

66779681472 is a wasteful number, since it uses less digits than its factorization.

66779681472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411 (or 389 counting only the distinct ones).

The product of its digits is 42674688, while the sum is 63.

The spelling of 66779681472 in words is "sixty-six billion, seven hundred seventy-nine million, six hundred eighty-one thousand, four hundred seventy-two".