81282745 has 4 divisors (see below), whose sum is σ = 97539300. Its totient is φ = 65026192.

The previous prime is 81282743. The next prime is 81282757. The reversal of 81282745 is 54728218.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54728218 = 2 ⋅27364109.

It can be written as a sum of positive squares in 2 ways, for example, as 59305401 + 21977344 = 7701^2 + 4688^2 .

It is a cyclic number.

It is not a de Polignac number, because 81282745 - 2¹ = 81282743 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81282743) 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 3 ways as a sum of consecutive naturals, for example, 8128270 + ... + 8128279.

It is an arithmetic number, because the mean of its divisors is an integer number (24384825).

Almost surely, 2^81282745 is an apocalyptic number.

It is an amenable number.

81282745 is a deficient number, since it is larger than the sum of its proper divisors (16256555).

81282745 is a wasteful number, since it uses less digits than its factorization.

81282745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16256554.

The product of its digits is 35840, while the sum is 37.

The square root of 81282745 is about 9015.6943714835. The cubic root of 81282745 is about 433.1777294701.

The spelling of 81282745 in words is "eighty-one million, two hundred eighty-two thousand, seven hundred forty-five".