66165640 has 32 divisors (see below), whose sum is σ = 150416280. Its totient is φ = 26191872.

The previous prime is 66165637. The next prime is 66165643. The reversal of 66165640 is 4656166.

It is an interprime number because it is at equal distance from previous prime (66165637) and next prime (66165643).

It can be written as a sum of positive squares in 4 ways, for example, as 47692836 + 18472804 = 6906^2 + 4298^2 .

It is a junction number, because it is equal to n+sod(n) for n = 66165596 and 66165605.

It is not an unprimeable number, because it can be changed into a prime (66165643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4647 + ... + 12406.

Almost surely, 2^66165640 is an apocalyptic number.

It is an amenable number.

66165640 is an abundant number, since it is smaller than the sum of its proper divisors (84250640).

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

66165640 is a wasteful number, since it uses less digits than its factorization.

66165640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17161 (or 17157 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 66165640 is about 8134.2264536955. The cubic root of 66165640 is about 404.4617958940.

The spelling of 66165640 in words is "sixty-six million, one hundred sixty-five thousand, six hundred forty".