81739694449 has 4 divisors (see below), whose sum is σ = 93416793664. Its totient is φ = 70062595236.

The previous prime is 81739694429. The next prime is 81739694467. The reversal of 81739694449 is 94449693718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81739694449 - 2⁵ = 81739694417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81739694429) 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, 5838549597 + ... + 5838549610.

It is an arithmetic number, because the mean of its divisors is an integer number (23354198416).

Almost surely, 2^81739694449 is an apocalyptic number.

It is an amenable number.

81739694449 is a deficient number, since it is larger than the sum of its proper divisors (11677099215).

81739694449 is a wasteful number, since it uses less digits than its factorization.

81739694449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11677099214.

The product of its digits is 47029248, while the sum is 64.

The spelling of 81739694449 in words is "eighty-one billion, seven hundred thirty-nine million, six hundred ninety-four thousand, four hundred forty-nine".