81738687 has 8 divisors (see below), whose sum is σ = 111303936. Its totient is φ = 53332952.

The previous prime is 81738677. The next prime is 81738731. The reversal of 81738687 is 78683718.

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 81738687 - 2⁶ = 81738623 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81738677) 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, 289713 + ... + 289994.

It is an arithmetic number, because the mean of its divisors is an integer number (13912992).

Almost surely, 2^81738687 is an apocalyptic number.

81738687 is a deficient number, since it is larger than the sum of its proper divisors (29565249).

81738687 is a wasteful number, since it uses less digits than its factorization.

81738687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 579757.

The product of its digits is 451584, while the sum is 48.

The square root of 81738687 is about 9040.9450280377. The cubic root of 81738687 is about 433.9861658257.

The spelling of 81738687 in words is "eighty-one million, seven hundred thirty-eight thousand, six hundred eighty-seven".