81056452405 has 4 divisors (see below), whose sum is σ = 97267742892. Its totient is φ = 64845161920.

The previous prime is 81056452333. The next prime is 81056452417. The reversal of 81056452405 is 50425465018.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16884923364 + 64171529041 = 129942^2 + 253321^2 .

It is not a de Polignac number, because 81056452405 - 2¹³ = 81056444213 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8105645236 + ... + 8105645245.

It is an arithmetic number, because the mean of its divisors is an integer number (24316935723).

Almost surely, 2^81056452405 is an apocalyptic number.

It is an amenable number.

81056452405 is a deficient number, since it is larger than the sum of its proper divisors (16211290487).

81056452405 is a wasteful number, since it uses less digits than its factorization.

81056452405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16211290486.

The product of its (nonzero) digits is 192000, while the sum is 40.

The spelling of 81056452405 in words is "eighty-one billion, fifty-six million, four hundred fifty-two thousand, four hundred five".