81520318829 has 8 divisors (see below), whose sum is σ = 81878958720. Its totient is φ = 81161754336.

The previous prime is 81520318799. The next prime is 81520318837. The reversal of 81520318829 is 92881302518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81520318829 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81520318849) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4115852 + ... + 4135610.

It is an arithmetic number, because the mean of its divisors is an integer number (10234869840).

Almost surely, 2^81520318829 is an apocalyptic number.

It is an amenable number.

81520318829 is a deficient number, since it is larger than the sum of its proper divisors (358639891).

81520318829 is a wasteful number, since it uses less digits than its factorization.

81520318829 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37699.

The product of its (nonzero) digits is 276480, while the sum is 47.

The spelling of 81520318829 in words is "eighty-one billion, five hundred twenty million, three hundred eighteen thousand, eight hundred twenty-nine".