81661731662 has 8 divisors (see below), whose sum is σ = 139991540016. Its totient is φ = 34997884992.

The previous prime is 81661731659. The next prime is 81661731667. The reversal of 81661731662 is 26613716618.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81661731667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2916490403 + ... + 2916490430.

It is an arithmetic number, because the mean of its divisors is an integer number (17498942502).

Almost surely, 2^81661731662 is an apocalyptic number.

81661731662 is a deficient number, since it is larger than the sum of its proper divisors (58329808354).

81661731662 is a wasteful number, since it uses less digits than its factorization.

81661731662 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5832980842.

The product of its digits is 435456, while the sum is 47.

The spelling of 81661731662 in words is "eighty-one billion, six hundred sixty-one million, seven hundred thirty-one thousand, six hundred sixty-two".