81976449777 has 8 divisors (see below), whose sum is σ = 109478513760. Its totient is φ = 54562676160.

The previous prime is 81976449773. The next prime is 81976449781. The reversal of 81976449777 is 77794467918.

It is an interprime number because it is at equal distance from previous prime (81976449773) and next prime (81976449781).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81976449777 - 2² = 81976449773 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81976449773) 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 7 ways as a sum of consecutive naturals, for example, 22070424 + ... + 22074137.

It is an arithmetic number, because the mean of its divisors is an integer number (13684814220).

Almost surely, 2^81976449777 is an apocalyptic number.

It is an amenable number.

81976449777 is a deficient number, since it is larger than the sum of its proper divisors (27502063983).

81976449777 is a wasteful number, since it uses less digits than its factorization.

81976449777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44145183.

The product of its digits is 149361408, while the sum is 69.

The spelling of 81976449777 in words is "eighty-one billion, nine hundred seventy-six million, four hundred forty-nine thousand, seven hundred seventy-seven".