81712787 has 8 divisors (see below), whose sum is σ = 92630160. Its totient is φ = 71457120.

The previous prime is 81712777. The next prime is 81712801. The reversal of 81712787 is 78721718.

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 81712787 - 2⁶ = 81712723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81712717) 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, 165164 + ... + 165657.

It is an arithmetic number, because the mean of its divisors is an integer number (11578770).

Almost surely, 2^81712787 is an apocalyptic number.

81712787 is a deficient number, since it is larger than the sum of its proper divisors (10917373).

81712787 is a wasteful number, since it uses less digits than its factorization.

81712787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330853.

The product of its digits is 43904, while the sum is 41.

The square root of 81712787 is about 9039.5125421673. The cubic root of 81712787 is about 433.9403228697.

The spelling of 81712787 in words is "eighty-one million, seven hundred twelve thousand, seven hundred eighty-seven".