66628730 has 24 divisors (see below), whose sum is σ = 139513428. Its totient is φ = 22843968.

The previous prime is 66628691. The next prime is 66628733. The reversal of 66628730 is 3782666.

It can be written as a sum of positive squares in 2 ways, for example, as 64915249 + 1713481 = 8057^2 + 1309^2 .

It is a super-2 number, since 2×66628730² = 8878775322825800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66628733) 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, 67499 + ... + 68478.

Almost surely, 2^66628730 is an apocalyptic number.

66628730 is an abundant number, since it is smaller than the sum of its proper divisors (72884698).

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

66628730 is a wasteful number, since it uses less digits than its factorization.

66628730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135998 (or 135991 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 38.

The square root of 66628730 is about 8162.6423417910. The cubic root of 66628730 is about 405.4032056213.

The spelling of 66628730 in words is "sixty-six million, six hundred twenty-eight thousand, seven hundred thirty".