80778409 has 2 divisors, whose sum is σ = 80778410. Its totient is φ = 80778408.

The previous prime is 80778361. The next prime is 80778421. The reversal of 80778409 is 90487708.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60886809 + 19891600 = 7803^2 + 4460^2 .

It is a cyclic number.

It is not a de Polignac number, because 80778409 - 2¹⁵ = 80745641 is a prime.

It is not a weakly prime, because it can be changed into another prime (80778449) 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, 40389204 + 40389205.

It is an arithmetic number, because the mean of its divisors is an integer number (40389205).

Almost surely, 2^80778409 is an apocalyptic number.

It is an amenable number.

80778409 is a deficient number, since it is larger than the sum of its proper divisors (1).

80778409 is an equidigital number, since it uses as much as digits as its factorization.

80778409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112896, while the sum is 43.

The square root of 80778409 is about 8987.6809578445. The cubic root of 80778409 is about 432.2799557823.

The spelling of 80778409 in words is "eighty million, seven hundred seventy-eight thousand, four hundred nine".