81739856029 has 4 divisors (see below), whose sum is σ = 88027537276. Its totient is φ = 75452174784.

The previous prime is 81739855993. The next prime is 81739856039. The reversal of 81739856029 is 92065893718.

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 22884125625 + 58855730404 = 151275^2 + 242602^2 .

It is a cyclic number.

It is not a de Polignac number, because 81739856029 - 2¹³ = 81739847837 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 (81739856039) 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, 3143840604 + ... + 3143840629.

It is an arithmetic number, because the mean of its divisors is an integer number (22006884319).

Almost surely, 2^81739856029 is an apocalyptic number.

It is an amenable number.

81739856029 is a deficient number, since it is larger than the sum of its proper divisors (6287681247).

81739856029 is a wasteful number, since it uses less digits than its factorization.

81739856029 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6287681246.

The product of its (nonzero) digits is 6531840, while the sum is 58.

The spelling of 81739856029 in words is "eighty-one billion, seven hundred thirty-nine million, eight hundred fifty-six thousand, twenty-nine".