81731566390 has 8 divisors (see below), whose sum is σ = 147116819520. Its totient is φ = 32692626552.

The previous prime is 81731566387. The next prime is 81731566403. The reversal of 81731566390 is 9366513718.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4086578310 + ... + 4086578329.

It is an arithmetic number, because the mean of its divisors is an integer number (18389602440).

Almost surely, 2^81731566390 is an apocalyptic number.

81731566390 is a deficient number, since it is larger than the sum of its proper divisors (65385253130).

81731566390 is a wasteful number, since it uses less digits than its factorization.

81731566390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8173156646.

The product of its (nonzero) digits is 816480, while the sum is 49.

The spelling of 81731566390 in words is "eighty-one billion, seven hundred thirty-one million, five hundred sixty-six thousand, three hundred ninety".