161811809726 has 32 divisors (see below), whose sum is σ = 282344251392. Its totient is φ = 68120589600.

The previous prime is 161811809717. The next prime is 161811809737. The reversal of 161811809726 is 627908118161.

It is a happy number.

It is a congruent number.

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, 270956 + ... + 630111.

It is an arithmetic number, because the mean of its divisors is an integer number (8823257856).

Almost surely, 2^161811809726 is an apocalyptic number.

161811809726 is a deficient number, since it is larger than the sum of its proper divisors (120532441666).

161811809726 is a wasteful number, since it uses less digits than its factorization.

161811809726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 901304.

The product of its (nonzero) digits is 290304, while the sum is 50.

The spelling of 161811809726 in words is "one hundred sixty-one billion, eight hundred eleven million, eight hundred nine thousand, seven hundred twenty-six".