80745781 has 2 divisors, whose sum is σ = 80745782. Its totient is φ = 80745780.

The previous prime is 80745779. The next prime is 80745809. The reversal of 80745781 is 18754708.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64545156 + 16200625 = 8034^2 + 4025^2 .

It is a cyclic number.

It is not a de Polignac number, because 80745781 - 2¹ = 80745779 is a prime.

It is a super-2 number, since 2×80745781² = 13039762298599922, which contains 22 as substring.

Together with 80745779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (80745751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40372890 + 40372891.

It is an arithmetic number, because the mean of its divisors is an integer number (40372891).

Almost surely, 2^80745781 is an apocalyptic number.

It is an amenable number.

80745781 is a deficient number, since it is larger than the sum of its proper divisors (1).

80745781 is an equidigital number, since it uses as much as digits as its factorization.

80745781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62720, while the sum is 40.

The square root of 80745781 is about 8985.8656232997. The cubic root of 80745781 is about 432.2217457977.

The spelling of 80745781 in words is "eighty million, seven hundred forty-five thousand, seven hundred eighty-one".