81685801 has 8 divisors (see below), whose sum is σ = 82268000. Its totient is φ = 81106272.

The previous prime is 81685789. The next prime is 81685819. The reversal of 81685801 is 10858618.

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 81685801 - 2¹⁹ = 81161513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81685831) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 155926 + ... + 156448.

It is an arithmetic number, because the mean of its divisors is an integer number (10283500).

Almost surely, 2^81685801 is an apocalyptic number.

It is an amenable number.

81685801 is a deficient number, since it is larger than the sum of its proper divisors (582199).

81685801 is a wasteful number, since it uses less digits than its factorization.

81685801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1335.

The product of its (nonzero) digits is 15360, while the sum is 37.

The square root of 81685801 is about 9038.0197499231. The cubic root of 81685801 is about 433.8925473895.

The spelling of 81685801 in words is "eighty-one million, six hundred eighty-five thousand, eight hundred one".