81736431829 has 4 divisors (see below), whose sum is σ = 88023849676. Its totient is φ = 75449013984.

The previous prime is 81736431773. The next prime is 81736431859. The reversal of 81736431829 is 92813463718.

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 50862427729 + 30874004100 = 225527^2 + 175710^2 .

It is a cyclic number.

It is not a de Polignac number, because 81736431829 - 2¹⁵ = 81736399061 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81736431859) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3143708904 + ... + 3143708929.

It is an arithmetic number, because the mean of its divisors is an integer number (22005962419).

Almost surely, 2^81736431829 is an apocalyptic number.

It is an amenable number.

81736431829 is a deficient number, since it is larger than the sum of its proper divisors (6287417847).

81736431829 is a wasteful number, since it uses less digits than its factorization.

81736431829 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6287417846.

The product of its digits is 1741824, while the sum is 52.

The spelling of 81736431829 in words is "eighty-one billion, seven hundred thirty-six million, four hundred thirty-one thousand, eight hundred twenty-nine".