81341321616 has 45 divisors (see below), whose sum is σ = 227652304971. Its totient is φ = 27112633056.

The previous prime is 81341321603. The next prime is 81341321617. The reversal of 81341321616 is 61612314318.

The square root of 81341321616 is 285204.

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

81341321616 is a `hidden beast` number, since 8 + 1 + 3 + 4 + 1 + 32 + 1 + 616 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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

It is not an unprimeable number, because it can be changed into a prime (81341321617) 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 8 ways as a sum of consecutive naturals, for example, 3410565 + ... + 3434331.

Almost surely, 2^81341321616 is an apocalyptic number.

81341321616 is the 285204-th square number.

It is an amenable number.

81341321616 is an abundant number, since it is smaller than the sum of its proper divisors (146310983355).

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

81341321616 is an frugal number, since it uses more digits than its factorization.

81341321616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47548 (or 23772 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

Multiplying 81341321616 by its sum of digits (36), we get a square (2928287578176 = 1711224²).

81341321616 divided by its sum of digits (36) gives a square (2259481156 = 47534²).

The spelling of 81341321616 in words is "eighty-one billion, three hundred forty-one million, three hundred twenty-one thousand, six hundred sixteen".