81785087 has 8 divisors (see below), whose sum is σ = 82656000. Its totient is φ = 80919000.

The previous prime is 81785071. The next prime is 81785111. The reversal of 81785087 is 78058718.

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 81785087 - 2⁴ = 81785071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81781087) 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, 39914 + ... + 41912.

It is an arithmetic number, because the mean of its divisors is an integer number (10332000).

Almost surely, 2^81785087 is an apocalyptic number.

81785087 is a deficient number, since it is larger than the sum of its proper divisors (870913).

81785087 is a wasteful number, since it uses less digits than its factorization.

81785087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2413.

The product of its (nonzero) digits is 125440, while the sum is 44.

The square root of 81785087 is about 9043.5107673956. The cubic root of 81785087 is about 434.0682695382.

The spelling of 81785087 in words is "eighty-one million, seven hundred eighty-five thousand, eighty-seven".