80005605781 has 4 divisors (see below), whose sum is σ = 80074996012. Its totient is φ = 79936215552.

The previous prime is 80005605749. The next prime is 80005605809. The reversal of 80005605781 is 18750650008.

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 33924114225 + 46081491556 = 184185^2 + 214666^2 .

It is a cyclic number.

It is not a de Polignac number, because 80005605781 - 2⁵ = 80005605749 is a prime.

It is a super-2 number, since 2×80005605781² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (80005606781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34693386 + ... + 34695691.

It is an arithmetic number, because the mean of its divisors is an integer number (20018749003).

Almost surely, 2^80005605781 is an apocalyptic number.

It is an amenable number.

80005605781 is a deficient number, since it is larger than the sum of its proper divisors (69390231).

80005605781 is a wasteful number, since it uses less digits than its factorization.

80005605781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69390230.

The product of its (nonzero) digits is 67200, while the sum is 40.

The spelling of 80005605781 in words is "eighty billion, five million, six hundred five thousand, seven hundred eighty-one".