81660845 has 8 divisors (see below), whose sum is σ = 111992064. Its totient is φ = 55995984.

The previous prime is 81660811. The next prime is 81660853. The reversal of 81660845 is 54806618.

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 81660845 - 2⁸ = 81660589 is a prime.

It is a super-2 number, since 2×81660845² = 13336987212228050, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81660799 and 81660808.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1166549 + ... + 1166618.

It is an arithmetic number, because the mean of its divisors is an integer number (13999008).

Almost surely, 2^81660845 is an apocalyptic number.

It is an amenable number.

81660845 is a deficient number, since it is larger than the sum of its proper divisors (30331219).

81660845 is a wasteful number, since it uses less digits than its factorization.

81660845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2333179.

The product of its (nonzero) digits is 46080, while the sum is 38.

The square root of 81660845 is about 9036.6390322951. The cubic root of 81660845 is about 433.8483564155.

The spelling of 81660845 in words is "eighty-one million, six hundred sixty thousand, eight hundred forty-five".