161805985436 has 24 divisors (see below), whose sum is σ = 287766750096. Its totient is φ = 79590107520.

The previous prime is 161805985433. The next prime is 161805985463. The reversal of 161805985436 is 634589508161.

161805985436 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×161805985436² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161805985433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 195905 + ... + 601656.

It is an arithmetic number, because the mean of its divisors is an integer number (11990281254).

Almost surely, 2^161805985436 is an apocalyptic number.

It is an amenable number.

161805985436 is a deficient number, since it is larger than the sum of its proper divisors (125960764660).

161805985436 is a wasteful number, since it uses less digits than its factorization.

161805985436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 798389 (or 798387 counting only the distinct ones).

The product of its (nonzero) digits is 6220800, while the sum is 56.

The spelling of 161805985436 in words is "one hundred sixty-one billion, eight hundred five million, nine hundred eighty-five thousand, four hundred thirty-six".