165120571 has 32 divisors (see below), whose sum is σ = 212760576. Its totient is φ = 124416000.

The previous prime is 165120551. The next prime is 165120607. The reversal of 165120571 is 175021561.

It is a 12-Lehmer number, since φ(165120571) divides (165120571-1)¹².

It is a cyclic number.

It is not a de Polignac number, because 165120571 - 2¹³ = 165112379 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165120521) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 609166 + ... + 609436.

It is an arithmetic number, because the mean of its divisors is an integer number (6648768).

Almost surely, 2^165120571 is an apocalyptic number.

165120571 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

165120571 is a deficient number, since it is larger than the sum of its proper divisors (47640005).

165120571 is a wasteful number, since it uses less digits than its factorization.

165120571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 523.

The product of its (nonzero) digits is 2100, while the sum is 28.

The square root of 165120571 is about 12849.9249414150. The cubic root of 165120571 is about 548.6142204142.

It can be divided in two parts, 1651 and 20571, that added together give a palindrome (22222).

The spelling of 165120571 in words is "one hundred sixty-five million, one hundred twenty thousand, five hundred seventy-one".