81789930128 has 10 divisors (see below), whose sum is σ = 158467989654. Its totient is φ = 40894965056.

The previous prime is 81789930121. The next prime is 81789930139. The reversal of 81789930128 is 82103998718.

It can be written as a sum of positive squares in only one way, i.e., 78507556864 + 3282373264 = 280192^2 + 57292^2 .

It is not an unprimeable number, because it can be changed into a prime (81789930121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2555935301 + ... + 2555935332.

Almost surely, 2^81789930128 is an apocalyptic number.

It is an amenable number.

81789930128 is a deficient number, since it is larger than the sum of its proper divisors (76678059526).

81789930128 is a wasteful number, since it uses less digits than its factorization.

81789930128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5111870641 (or 5111870635 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 56.

The spelling of 81789930128 in words is "eighty-one billion, seven hundred eighty-nine million, nine hundred thirty thousand, one hundred twenty-eight".