81777881472 has 576 divisors, whose sum is σ = 277066272000. Its totient is φ = 20928872448.

The previous prime is 81777881461. The next prime is 81777881473. The reversal of 81777881472 is 27418877718.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81777881473) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 410944029 + ... + 410944227.

Almost surely, 2^81777881472 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81777881472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138533136000).

81777881472 is an abundant number, since it is smaller than the sum of its proper divisors (195288390528).

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

81777881472 is a wasteful number, since it uses less digits than its factorization.

81777881472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303 (or 251 counting only the distinct ones).

The product of its digits is 9834496, while the sum is 60.

The spelling of 81777881472 in words is "eighty-one billion, seven hundred seventy-seven million, eight hundred eighty-one thousand, four hundred seventy-two".