81878388736 has 117 divisors (see below), whose sum is σ = 174598790821. Its totient is φ = 38384500736.

The previous prime is 81878388707. The next prime is 81878388773. The reversal of 81878388736 is 63788387818.

The square root of 81878388736 is 286144.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 63746150400 + 18132238336 = 252480^2 + 134656^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 311324541 + ... + 311324803.

Almost surely, 2^81878388736 is an apocalyptic number.

81878388736 is the 286144-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81878388736

81878388736 is an abundant number, since it is smaller than the sum of its proper divisors (92720402085).

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

81878388736 is an frugal number, since it uses more digits than its factorization.

81878388736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 584 (or 282 counting only the distinct ones).

The product of its digits is 86704128, while the sum is 67.

The spelling of 81878388736 in words is "eighty-one billion, eight hundred seventy-eight million, three hundred eighty-eight thousand, seven hundred thirty-six".