66799728 has 160 divisors (see below), whose sum is σ = 204986880. Its totient is φ = 21041856.

The previous prime is 66799721. The next prime is 66799753. The reversal of 66799728 is 82799766.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66799721) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 804775 + ... + 804857.

It is an arithmetic number, because the mean of its divisors is an integer number (1281168).

Almost surely, 2^66799728 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 66799728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102493440).

66799728 is an abundant number, since it is smaller than the sum of its proper divisors (138187152).

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

66799728 is an equidigital number, since it uses as much as digits as its factorization.

66799728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 111 counting only the distinct ones).

The product of its digits is 2286144, while the sum is 54.

The square root of 66799728 is about 8173.1100567654. The cubic root of 66799728 is about 405.7497223938.

The spelling of 66799728 in words is "sixty-six million, seven hundred ninety-nine thousand, seven hundred twenty-eight".