81279835274089 has 3 divisors (see below), whose sum is σ = 81279844289623. Its totient is φ = 81279826258556.

The previous prime is 81279835274051. The next prime is 81279835274101. The reversal of 81279835274089 is 98047253897218.

The square root of 81279835274089 is 9015533.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 38410183784025 + 42869651490064 = 6197595^2 + 6547492^2 .

It is not a de Polignac number, because 81279835274089 - 2⁹ = 81279835273577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81279833274089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 4507767 + ... + 13523299.

Almost surely, 2^{81279835274089} is an apocalyptic number.

81279835274089 is the 9015533-rd square number.

81279835274089 is the 4507767-th centered octagonal number.

It is an amenable number.

81279835274089 is a deficient number, since it is larger than the sum of its proper divisors (9015534).

81279835274089 is an frugal number, since it uses more digits than its factorization.

81279835274089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18031066 (or 9015533 counting only the distinct ones).

The product of its (nonzero) digits is 487710720, while the sum is 73.

The spelling of 81279835274089 in words is "eighty-one trillion, two hundred seventy-nine billion, eight hundred thirty-five million, two hundred seventy-four thousand, eighty-nine".