81665134 has 8 divisors (see below), whose sum is σ = 127823760. Its totient is φ = 39057216.

The previous prime is 81665117. The next prime is 81665149. The reversal of 81665134 is 43156618.

It is a happy number.

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

It is a super-2 number, since 2×81665134² = 13338388222475912, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81665134.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 887619 + ... + 887710.

It is an arithmetic number, because the mean of its divisors is an integer number (15977970).

Almost surely, 2^81665134 is an apocalyptic number.

81665134 is a deficient number, since it is larger than the sum of its proper divisors (46158626).

81665134 is a wasteful number, since it uses less digits than its factorization.

81665134 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1775354.

The product of its digits is 17280, while the sum is 34.

The square root of 81665134 is about 9036.8763408603. The cubic root of 81665134 is about 433.8559518264.

The spelling of 81665134 in words is "eighty-one million, six hundred sixty-five thousand, one hundred thirty-four".