80780728421 has 4 divisors (see below), whose sum is σ = 81199281612. Its totient is φ = 80362175232.

The previous prime is 80780728397. The next prime is 80780728459. The reversal of 80780728421 is 12482708708.

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 21524997796 + 59255730625 = 146714^2 + 243425^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-80780728421 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 (80785728421) 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, 209276306 + ... + 209276691.

It is an arithmetic number, because the mean of its divisors is an integer number (20299820403).

Almost surely, 2^80780728421 is an apocalyptic number.

It is an amenable number.

80780728421 is a deficient number, since it is larger than the sum of its proper divisors (418553191).

80780728421 is a wasteful number, since it uses less digits than its factorization.

80780728421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418553190.

The product of its (nonzero) digits is 401408, while the sum is 47.

The spelling of 80780728421 in words is "eighty billion, seven hundred eighty million, seven hundred twenty-eight thousand, four hundred twenty-one".