66028581 has 16 divisors (see below), whose sum is σ = 98334720. Its totient is φ = 43787520.

The previous prime is 66028559. The next prime is 66028597. The reversal of 66028581 is 18582066.

It is a happy number.

It is not a de Polignac number, because 66028581 - 2¹⁰ = 66027557 is a prime.

It is a super-2 number, since 2×66028581² = 8719547017747122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66028511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1125 + ... + 11546.

It is an arithmetic number, because the mean of its divisors is an integer number (6145920).

Almost surely, 2^66028581 is an apocalyptic number.

It is an amenable number.

66028581 is a deficient number, since it is larger than the sum of its proper divisors (32306139).

66028581 is a wasteful number, since it uses less digits than its factorization.

66028581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12873 (or 12867 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 66028581 is about 8125.7972531931. The cubic root of 66028581 is about 404.1823283311.

It can be divided in two parts, 660 and 28581, that added together give a square (29241 = 171²).

The spelling of 66028581 in words is "sixty-six million, twenty-eight thousand, five hundred eighty-one".