165708821540 has 12 divisors (see below), whose sum is σ = 347988525276. Its totient is φ = 66283528608.

The previous prime is 165708821539. The next prime is 165708821543. The reversal of 165708821540 is 45128807561.

It can be written as a sum of positive squares in 2 ways, for example, as 115235807296 + 50473014244 = 339464^2 + 224662^2 .

It is not an unprimeable number, because it can be changed into a prime (165708821543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4142720519 + ... + 4142720558.

It is an arithmetic number, because the mean of its divisors is an integer number (28999043773).

Almost surely, 2^165708821540 is an apocalyptic number.

165708821540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165708821540 is an abundant number, since it is smaller than the sum of its proper divisors (182279703736).

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

165708821540 is a wasteful number, since it uses less digits than its factorization.

165708821540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8285441086 (or 8285441084 counting only the distinct ones).

The product of its (nonzero) digits is 537600, while the sum is 47.

The spelling of 165708821540 in words is "one hundred sixty-five billion, seven hundred eight million, eight hundred twenty-one thousand, five hundred forty".