81953765780 has 12 divisors (see below), whose sum is σ = 172102908180. Its totient is φ = 32781506304.

The previous prime is 81953765759. The next prime is 81953765837. The reversal of 81953765780 is 8756735918.

It can be written as a sum of positive squares in 2 ways, for example, as 64720377604 + 17233388176 = 254402^2 + 131276^2 .

It is a congruent number.

It is an unprimeable number.

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, 2048844125 + ... + 2048844164.

It is an arithmetic number, because the mean of its divisors is an integer number (14341909015).

Almost surely, 2^81953765780 is an apocalyptic number.

It is an amenable number.

81953765780 is an abundant number, since it is smaller than the sum of its proper divisors (90149142400).

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

81953765780 is a wasteful number, since it uses less digits than its factorization.

81953765780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4097688298 (or 4097688296 counting only the distinct ones).

The product of its (nonzero) digits is 12700800, while the sum is 59.

The spelling of 81953765780 in words is "eighty-one billion, nine hundred fifty-three million, seven hundred sixty-five thousand, seven hundred eighty".