165541621406931 has 72 divisors (see below), whose sum is σ = 308495006313312. Its totient is φ = 83671440652800.

The previous prime is 165541621406929. The next prime is 165541621406939. The reversal of 165541621406931 is 139604126145561.

165541621406931 is a `hidden beast` number, since 1 + 6 + 5 + 5 + 4 + 1 + 621 + 4 + 0 + 6 + 9 + 3 + 1 = 666.

It is not a de Polignac number, because 165541621406931 - 2¹ = 165541621406929 is a prime.

It is a super-2 number, since 2×165541621406931² (a number of 29 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (165541621406939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 293178390 + ... + 293742491.

Almost surely, 2^{165541621406931} is an apocalyptic number.

165541621406931 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

165541621406931 is a deficient number, since it is larger than the sum of its proper divisors (142953384906381).

165541621406931 is a wasteful number, since it uses less digits than its factorization.

165541621406931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586920953 (or 586920939 counting only the distinct ones).

The product of its (nonzero) digits is 4665600, while the sum is 54.

The spelling of 165541621406931 in words is "one hundred sixty-five trillion, five hundred forty-one billion, six hundred twenty-one million, four hundred six thousand, nine hundred thirty-one".