81739761 has 16 divisors (see below), whose sum is σ = 110808000. Its totient is φ = 53590208.

The previous prime is 81739717. The next prime is 81739783. The reversal of 81739761 is 16793718.

It is a cyclic number.

It is not a de Polignac number, because 81739761 - 2¹³ = 81731569 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (81739061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46975 + ... + 48683.

It is an arithmetic number, because the mean of its divisors is an integer number (6925500).

Almost surely, 2^81739761 is an apocalyptic number.

It is an amenable number.

81739761 is a deficient number, since it is larger than the sum of its proper divisors (29068239).

81739761 is a wasteful number, since it uses less digits than its factorization.

81739761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1968.

The product of its digits is 63504, while the sum is 42.

The square root of 81739761 is about 9041.0044242883. The cubic root of 81739761 is about 433.9880665948.

The spelling of 81739761 in words is "eighty-one million, seven hundred thirty-nine thousand, seven hundred sixty-one".