81329354739 has 24 divisors (see below), whose sum is σ = 119420235792. Its totient is φ = 53329436160.

The previous prime is 81329354719. The next prime is 81329354791. The reversal of 81329354739 is 93745392318.

81329354739 is a `hidden beast` number, since 8 + 1 + 3 + 2 + 93 + 547 + 3 + 9 = 666.

It is not a de Polignac number, because 81329354739 - 2¹¹ = 81329352691 is a prime.

It is a super-2 number, since 2×81329354739² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81329354719) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 172002 + ... + 438455.

It is an arithmetic number, because the mean of its divisors is an integer number (4975843158).

Almost surely, 2^81329354739 is an apocalyptic number.

81329354739 is a deficient number, since it is larger than the sum of its proper divisors (38090881053).

81329354739 is a wasteful number, since it uses less digits than its factorization.

81329354739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 610707 (or 610704 counting only the distinct ones).

The product of its digits is 4898880, while the sum is 54.

The spelling of 81329354739 in words is "eighty-one billion, three hundred twenty-nine million, three hundred fifty-four thousand, seven hundred thirty-nine".