81742189656 has 32 divisors (see below), whose sum is σ = 207705567600. Its totient is φ = 26800717440.

The previous prime is 81742189631. The next prime is 81742189657. The reversal of 81742189656 is 65698124718.

It is a junction number, because it is equal to n+sod(n) for n = 81742189596 and 81742189605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81742189657) 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, 27915951 + ... + 27918878.

Almost surely, 2^81742189656 is an apocalyptic number.

It is an amenable number.

81742189656 is an abundant number, since it is smaller than the sum of its proper divisors (125963377944).

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

81742189656 is a wasteful number, since it uses less digits than its factorization.

81742189656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55834899 (or 55834895 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 57.

The spelling of 81742189656 in words is "eighty-one billion, seven hundred forty-two million, one hundred eighty-nine thousand, six hundred fifty-six".