81727749494 has 4 divisors (see below), whose sum is σ = 122591624244. Its totient is φ = 40863874746.

The previous prime is 81727749457. The next prime is 81727749533. The reversal of 81727749494 is 49494772718.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20431937372 + ... + 20431937375.

It is an arithmetic number, because the mean of its divisors is an integer number (30647906061).

Almost surely, 2^81727749494 is an apocalyptic number.

81727749494 is a deficient number, since it is larger than the sum of its proper divisors (40863874750).

81727749494 is a wasteful number, since it uses less digits than its factorization.

81727749494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40863874749.

The product of its digits is 28449792, while the sum is 62.

The spelling of 81727749494 in words is "eighty-one billion, seven hundred twenty-seven million, seven hundred forty-nine thousand, four hundred ninety-four".