165680640 has 400 divisors, whose sum is σ = 641691072. Its totient is φ = 40697856.

The previous prime is 165680629. The next prime is 165680651. The reversal of 165680640 is 46086561.

165680640 is a `hidden beast` number, since 1 + 6 + 5 + 6 + 8 + 0 + 640 = 666.

It is an interprime number because it is at equal distance from previous prime (165680629) and next prime (165680651).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 165680595 and 165680604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3525097 + ... + 3525143.

Almost surely, 2^165680640 is an apocalyptic number.

165680640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165680640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (320845536).

165680640 is an abundant number, since it is smaller than the sum of its proper divisors (476010432).

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

165680640 is an equidigital number, since it uses as much as digits as its factorization.

165680640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99 (or 74 counting only the distinct ones).

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

The square root of 165680640 is about 12871.6991885299. The cubic root of 165680640 is about 549.2337981179.

The spelling of 165680640 in words is "one hundred sixty-five million, six hundred eighty thousand, six hundred forty".