66645081 has 6 divisors (see below), whose sum is σ = 96265130. Its totient is φ = 44430048.

The previous prime is 66645077. The next prime is 66645097. The reversal of 66645081 is 18054666.

It can be written as a sum of positive squares in only one way, i.e., 35105625 + 31539456 = 5925^2 + 5616^2 .

It is not a de Polignac number, because 66645081 - 2² = 66645077 is a prime.

It is a super-2 number, since 2×66645081² = 8883133642993122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66645031) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3702496 + ... + 3702513.

Almost surely, 2^66645081 is an apocalyptic number.

It is an amenable number.

66645081 is a deficient number, since it is larger than the sum of its proper divisors (29620049).

66645081 is a wasteful number, since it uses less digits than its factorization.

66645081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7405015 (or 7405012 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 66645081 is about 8163.6438555341. The cubic root of 66645081 is about 405.4363655192.

The spelling of 66645081 in words is "sixty-six million, six hundred forty-five thousand, eighty-one".