81928217365 has 16 divisors (see below), whose sum is σ = 101079892080. Its totient is φ = 63702374400.

The previous prime is 81928217359. The next prime is 81928217377. The reversal of 81928217365 is 56371282918.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 1048270129 + 80879947236 = 32377^2 + 284394^2 .

It is a de Polignac number, because none of the positive numbers 2^k-81928217365 is a prime.

It is a congruent number.

It is an unprimeable number.

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, 66486 + ... + 410215.

It is an arithmetic number, because the mean of its divisors is an integer number (6317493255).

Almost surely, 2^81928217365 is an apocalyptic number.

It is an amenable number.

81928217365 is a deficient number, since it is larger than the sum of its proper divisors (19151674715).

81928217365 is a wasteful number, since it uses less digits than its factorization.

81928217365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 477672.

The product of its digits is 1451520, while the sum is 52.

The spelling of 81928217365 in words is "eighty-one billion, nine hundred twenty-eight million, two hundred seventeen thousand, three hundred sixty-five".