161661726 has 24 divisors (see below), whose sum is σ = 352792440. Its totient is φ = 53498736.

The previous prime is 161661707. The next prime is 161661739. The reversal of 161661726 is 627166161.

161661726 is a `hidden beast` number, since 1 + 6 + 16 + 617 + 26 = 666.

It is a super-2 number, since 2×161661726² = 52269027306598152, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29805 + ... + 34808.

It is an arithmetic number, because the mean of its divisors is an integer number (14699685).

Almost surely, 2^161661726 is an apocalyptic number.

161661726 is an abundant number, since it is smaller than the sum of its proper divisors (191130714).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161661726 is a wasteful number, since it uses less digits than its factorization.

161661726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64760 (or 64757 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 161661726 is about 12714.6264593184. The cubic root of 161661726 is about 544.7564784720.

The spelling of 161661726 in words is "one hundred sixty-one million, six hundred sixty-one thousand, seven hundred twenty-six".