161661115506011 has 8 divisors (see below), whose sum is σ = 176373854335344. Its totient is φ = 146951088973920.

The previous prime is 161661115505921. The next prime is 161661115506061. The reversal of 161661115506011 is 110605511166161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-161661115506011 is a prime.

It is a super-2 number, since 2×161661115506011² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161661115506011.

It is not an unprimeable number, because it can be changed into a prime (161661115506061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 677949680 + ... + 678188093.

It is an arithmetic number, because the mean of its divisors is an integer number (22046731791918).

Almost surely, 2^{161661115506011} is an apocalyptic number.

161661115506011 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

161661115506011 is a deficient number, since it is larger than the sum of its proper divisors (14712738829333).

161661115506011 is a wasteful number, since it uses less digits than its factorization.

161661115506011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1356148621.

The product of its (nonzero) digits is 32400, while the sum is 41.

The spelling of 161661115506011 in words is "one hundred sixty-one trillion, six hundred sixty-one billion, one hundred fifteen million, five hundred six thousand, eleven".