81350578120 has 48 divisors (see below), whose sum is σ = 212922691740. Its totient is φ = 27891626112.

The previous prime is 81350578079. The next prime is 81350578123. The reversal of 81350578120 is 2187505318.

It can be written as a sum of positive squares in 2 ways, for example, as 80269089124 + 1081488996 = 283318^2 + 32886^2 .

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 (81350578123) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20750739 + ... + 20754658.

Almost surely, 2^81350578120 is an apocalyptic number.

It is an amenable number.

81350578120 is an abundant number, since it is smaller than the sum of its proper divisors (131572113620).

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

81350578120 is a wasteful number, since it uses less digits than its factorization.

81350578120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41505422 (or 41505411 counting only the distinct ones).

The product of its (nonzero) digits is 67200, while the sum is 40.

The spelling of 81350578120 in words is "eighty-one billion, three hundred fifty million, five hundred seventy-eight thousand, one hundred twenty".