81783253120 has 32 divisors (see below), whose sum is σ = 195513091020. Its totient is φ = 32713300992.

The previous prime is 81783253109. The next prime is 81783253127. The reversal of 81783253120 is 2135238718.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 66353638464 + 15429614656 = 257592^2 + 124216^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (81783253127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63892527 + ... + 63893806.

Almost surely, 2^81783253120 is an apocalyptic number.

81783253120 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81783253120 is an abundant number, since it is smaller than the sum of its proper divisors (113729837900).

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

81783253120 is a wasteful number, since it uses less digits than its factorization.

81783253120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127786352 (or 127786340 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 40.

The spelling of 81783253120 in words is "eighty-one billion, seven hundred eighty-three million, two hundred fifty-three thousand, one hundred twenty".