81798687 has 8 divisors (see below), whose sum is σ = 121183280. Its totient is φ = 54532440.

The previous prime is 81798683. The next prime is 81798697. The reversal of 81798687 is 78689718.

It is not a de Polignac number, because 81798687 - 2² = 81798683 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 (81798683) 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, 1514764 + ... + 1514817.

It is an arithmetic number, because the mean of its divisors is an integer number (15147910).

Almost surely, 2^81798687 is an apocalyptic number.

81798687 is a deficient number, since it is larger than the sum of its proper divisors (39384593).

81798687 is a wasteful number, since it uses less digits than its factorization.

81798687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3029590 (or 3029584 counting only the distinct ones).

The product of its digits is 1354752, while the sum is 54.

The square root of 81798687 is about 9044.2626565132. The cubic root of 81798687 is about 434.0923285343.

The spelling of 81798687 in words is "eighty-one million, seven hundred ninety-eight thousand, six hundred eighty-seven".