81705420692 has 48 divisors (see below), whose sum is σ = 168860869632. Its totient is φ = 33851139840.

The previous prime is 81705420677. The next prime is 81705420703. The reversal of 81705420692 is 29602450718.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 777818 + ... + 876590.

It is an arithmetic number, because the mean of its divisors is an integer number (3517934784).

Almost surely, 2^81705420692 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81705420692, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84430434816).

81705420692 is an abundant number, since it is smaller than the sum of its proper divisors (87155448940).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81705420692 is a wasteful number, since it uses less digits than its factorization.

81705420692 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99768 (or 99766 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 44.

The spelling of 81705420692 in words is "eighty-one billion, seven hundred five million, four hundred twenty thousand, six hundred ninety-two".