81606161 has 8 divisors (see below), whose sum is σ = 100438464. Its totient is φ = 64567440.

The previous prime is 81606157. The next prime is 81606191. The reversal of 81606161 is 16160618.

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

It is not a de Polignac number, because 81606161 - 2² = 81606157 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81606101) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 448295 + ... + 448476.

It is an arithmetic number, because the mean of its divisors is an integer number (12554808).

Almost surely, 2^81606161 is an apocalyptic number.

It is an amenable number.

81606161 is a deficient number, since it is larger than the sum of its proper divisors (18832303).

81606161 is a wasteful number, since it uses less digits than its factorization.

81606161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 896791.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 81606161 is about 9033.6128431542. The cubic root of 81606161 is about 433.7514929342.

Adding to 81606161 its reverse (16160618), we get a palindrome (97766779).

The spelling of 81606161 in words is "eighty-one million, six hundred six thousand, one hundred sixty-one".