81657677 has 4 divisors (see below), whose sum is σ = 82406940. Its totient is φ = 80908416.

The previous prime is 81657673. The next prime is 81657701. The reversal of 81657677 is 77675618.

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

It can be written as a sum of positive squares in 2 ways, for example, as 55145476 + 26512201 = 7426^2 + 5149^2 .

It is a cyclic number.

It is not a de Polignac number, because 81657677 - 2² = 81657673 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81657673) 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 3 ways as a sum of consecutive naturals, for example, 374468 + ... + 374685.

It is an arithmetic number, because the mean of its divisors is an integer number (20601735).

Almost surely, 2^81657677 is an apocalyptic number.

It is an amenable number.

81657677 is a deficient number, since it is larger than the sum of its proper divisors (749263).

81657677 is a wasteful number, since it uses less digits than its factorization.

81657677 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 749262.

The product of its digits is 493920, while the sum is 47.

The square root of 81657677 is about 9036.4637441867. The cubic root of 81657677 is about 433.8427460181.

The spelling of 81657677 in words is "eighty-one million, six hundred fifty-seven thousand, six hundred seventy-seven".