165761640 has 160 divisors (see below), whose sum is σ = 607923360. Its totient is φ = 40176000.

The previous prime is 165761599. The next prime is 165761677. The reversal of 165761640 is 46167561.

165761640 is a `hidden beast` number, since 1 + 6 + 5 + 7 + 6 + 1 + 640 = 666.

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 = 165761595 and 165761604.

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, 33315 + ... + 37965.

It is an arithmetic number, because the mean of its divisors is an integer number (3799521).

Almost surely, 2^165761640 is an apocalyptic number.

165761640 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 165761640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (303961680).

165761640 is an abundant number, since it is smaller than the sum of its proper divisors (442161720).

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

165761640 is a wasteful number, since it uses less digits than its factorization.

165761640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4685 (or 4672 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 165761640 is about 12874.8452417883. The cubic root of 165761640 is about 549.3232889393.

The spelling of 165761640 in words is "one hundred sixty-five million, seven hundred sixty-one thousand, six hundred forty".