81684885 has 8 divisors (see below), whose sum is σ = 130695840. Its totient is φ = 43565264.

The previous prime is 81684853. The next prime is 81684893. The reversal of 81684885 is 58848618.

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 81684885 - 2⁵ = 81684853 is a prime.

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, 2722815 + ... + 2722844.

It is an arithmetic number, because the mean of its divisors is an integer number (16336980).

Almost surely, 2^81684885 is an apocalyptic number.

It is an amenable number.

81684885 is a deficient number, since it is larger than the sum of its proper divisors (49010955).

81684885 is a wasteful number, since it uses less digits than its factorization.

81684885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5445667.

The product of its digits is 491520, while the sum is 48.

The square root of 81684885 is about 9037.9690749637. The cubic root of 81684885 is about 433.8909255366.

The spelling of 81684885 in words is "eighty-one million, six hundred eighty-four thousand, eight hundred eighty-five".