165136631561 has 16 divisors (see below), whose sum is σ = 185479797888. Its totient is φ = 145719100800.

The previous prime is 165136631537. The next prime is 165136631587.

165136631561 is nontrivially palindromic in base 10.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165136631561 is a prime.

It is a super-2 number, since 2×165136631561² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (165136631531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 840485 + ... + 1018178.

It is an arithmetic number, because the mean of its divisors is an integer number (11592487368).

Almost surely, 2^165136631561 is an apocalyptic number.

165136631561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165136631561 is a deficient number, since it is larger than the sum of its proper divisors (20343166327).

165136631561 is a wasteful number, since it uses less digits than its factorization.

165136631561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1858912.

The product of its digits is 291600, while the sum is 44.

It can be divided in two parts, 165136 and 631561, that added together give a palindrome (796697).

The spelling of 165136631561 in words is "one hundred sixty-five billion, one hundred thirty-six million, six hundred thirty-one thousand, five hundred sixty-one".