80218979521 has 4 divisors (see below), whose sum is σ = 80284252500. Its totient is φ = 80153706544.

The previous prime is 80218979461. The next prime is 80218979531. The reversal of 80218979521 is 12597981208.

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 67553727921 + 12665251600 = 259911^2 + 112540^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-80218979521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (80218979531) 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, 32634646 + ... + 32637103.

It is an arithmetic number, because the mean of its divisors is an integer number (20071063125).

Almost surely, 2^80218979521 is an apocalyptic number.

It is an amenable number.

80218979521 is a deficient number, since it is larger than the sum of its proper divisors (65272979).

80218979521 is a wasteful number, since it uses less digits than its factorization.

80218979521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65272978.

The product of its (nonzero) digits is 725760, while the sum is 52.

The spelling of 80218979521 in words is "eighty billion, two hundred eighteen million, nine hundred seventy-nine thousand, five hundred twenty-one".