165221515065505 has 16 divisors (see below), whose sum is σ = 198900552638160. Its totient is φ = 131754061191168.

The previous prime is 165221515065491. The next prime is 165221515065533. The reversal of 165221515065505 is 505560515122561.

It can be written as a sum of positive squares in 8 ways, for example, as 210200242576 + 165011314822929 = 458476^2 + 12845673^2 .

It is a cyclic number.

It is not a de Polignac number, because 165221515065505 - 2⁷ = 165221515065377 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 360273291 + ... + 360731599.

It is an arithmetic number, because the mean of its divisors is an integer number (12431284539885).

Almost surely, 2^{165221515065505} is an apocalyptic number.

It is an amenable number.

165221515065505 is a deficient number, since it is larger than the sum of its proper divisors (33679037572655).

165221515065505 is a wasteful number, since it uses less digits than its factorization.

165221515065505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 688980.

The product of its (nonzero) digits is 2250000, while the sum is 49.

The spelling of 165221515065505 in words is "one hundred sixty-five trillion, two hundred twenty-one billion, five hundred fifteen million, sixty-five thousand, five hundred five".