71661605 has 8 divisors (see below), whose sum is σ = 87823872. Its totient is φ = 56109328.

The previous prime is 71661599. The next prime is 71661661. The reversal of 71661605 is 50616617.

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

It is a cyclic number.

It is not a de Polignac number, because 71661605 - 2¹⁰ = 71660581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 152237 + ... + 152706.

It is an arithmetic number, because the mean of its divisors is an integer number (10977984).

Almost surely, 2^71661605 is an apocalyptic number.

It is an amenable number.

71661605 is a deficient number, since it is larger than the sum of its proper divisors (16162267).

71661605 is a wasteful number, since it uses less digits than its factorization.

71661605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304995.

The product of its (nonzero) digits is 7560, while the sum is 32.

The square root of 71661605 is about 8465.3177731258. The cubic root of 71661605 is about 415.3639909082.

The spelling of 71661605 in words is "seventy-one million, six hundred sixty-one thousand, six hundred five".