66565644 has 24 divisors (see below), whose sum is σ = 155453760. Its totient is φ = 22169424.

The previous prime is 66565633. The next prime is 66565651. The reversal of 66565644 is 44656566.

It is a happy number.

It is a super-2 number, since 2×66565644² = 8861969922269472, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66565596 and 66565605.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22347 + ... + 25149.

It is an arithmetic number, because the mean of its divisors is an integer number (6477240).

Almost surely, 2^66565644 is an apocalyptic number.

It is an amenable number.

66565644 is an abundant number, since it is smaller than the sum of its proper divisors (88888116).

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

66565644 is a wasteful number, since it uses less digits than its factorization.

66565644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4789 (or 4787 counting only the distinct ones).

The product of its digits is 518400, while the sum is 42.

The square root of 66565644 is about 8158.7771142494. Note that the first 3 decimals coincide. The cubic root of 66565644 is about 405.2752160755.

The spelling of 66565644 in words is "sixty-six million, five hundred sixty-five thousand, six hundred forty-four".