81362239369 has 4 divisors (see below), whose sum is σ = 84167833860. Its totient is φ = 78556644880.

The previous prime is 81362239349. The next prime is 81362239379. The reversal of 81362239369 is 96393226318.

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 55981926025 + 25380313344 = 236605^2 + 159312^2 .

It is a cyclic number.

It is not a de Polignac number, because 81362239369 - 2⁹ = 81362238857 is a prime.

It is a super-2 number, since 2×81362239369² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81362239319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1402797202 + ... + 1402797259.

It is an arithmetic number, because the mean of its divisors is an integer number (21041958465).

Almost surely, 2^81362239369 is an apocalyptic number.

It is an amenable number.

81362239369 is a deficient number, since it is larger than the sum of its proper divisors (2805594491).

81362239369 is a wasteful number, since it uses less digits than its factorization.

81362239369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2805594490.

The product of its digits is 2519424, while the sum is 52.

The spelling of 81362239369 in words is "eighty-one billion, three hundred sixty-two million, two hundred thirty-nine thousand, three hundred sixty-nine".