66428928 has 168 divisors, whose sum is σ = 207015588. Its totient is φ = 20447232.

The previous prime is 66428927. The next prime is 66428941. The reversal of 66428928 is 82982466.

It can be written as a sum of positive squares in 2 ways, for example, as 61968384 + 4460544 = 7872^2 + 2112^2 .

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

It is a zygodrome in base 4.

It is not an unprimeable number, because it can be changed into a prime (66428927) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1253350 + ... + 1253402.

Almost surely, 2^66428928 is an apocalyptic number.

66428928 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66428928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103507794).

66428928 is an abundant number, since it is smaller than the sum of its proper divisors (140586660).

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

66428928 is a wasteful number, since it uses less digits than its factorization.

66428928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102 (or 75 counting only the distinct ones).

The product of its digits is 331776, while the sum is 45.

The square root of 66428928 is about 8150.3943462878. The cubic root of 66428928 is about 404.9975674294.

It can be divided in two parts, 664 and 28928, that added together give a palindrome (29592).

The spelling of 66428928 in words is "sixty-six million, four hundred twenty-eight thousand, nine hundred twenty-eight".