81079200977 has 4 divisors (see below), whose sum is σ = 81149522340. Its totient is φ = 81008879616.

The previous prime is 81079200919. The next prime is 81079201013. The reversal of 81079200977 is 77900297018.

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 72753733441 + 8325467536 = 269729^2 + 91244^2 .

It is a cyclic number.

It is not a de Polignac number, because 81079200977 - 2¹² = 81079196881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81079200577) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35158952 + ... + 35161257.

It is an arithmetic number, because the mean of its divisors is an integer number (20287380585).

Almost surely, 2^81079200977 is an apocalyptic number.

It is an amenable number.

81079200977 is a deficient number, since it is larger than the sum of its proper divisors (70321363).

81079200977 is a wasteful number, since it uses less digits than its factorization.

81079200977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70321362.

The product of its (nonzero) digits is 444528, while the sum is 50.

The spelling of 81079200977 in words is "eighty-one billion, seventy-nine million, two hundred thousand, nine hundred seventy-seven".