81374776780 has 48 divisors (see below), whose sum is σ = 186519632544. Its totient is φ = 29575365120.

The previous prime is 81374776771. The next prime is 81374776781. The reversal of 81374776780 is 8767747318.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (81374776781) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 329584 + ... + 520936.

It is an arithmetic number, because the mean of its divisors is an integer number (3885825678).

Almost surely, 2^81374776780 is an apocalyptic number.

It is an amenable number.

81374776780 is an abundant number, since it is smaller than the sum of its proper divisors (105144855764).

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

81374776780 is a wasteful number, since it uses less digits than its factorization.

81374776780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193306 (or 193304 counting only the distinct ones).

The product of its (nonzero) digits is 11063808, while the sum is 58.

The spelling of 81374776780 in words is "eighty-one billion, three hundred seventy-four million, seven hundred seventy-six thousand, seven hundred eighty".