78782581 has 2 divisors, whose sum is σ = 78782582. Its totient is φ = 78782580.

The previous prime is 78782503. The next prime is 78782597. The reversal of 78782581 is 18528787.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47141956 + 31640625 = 6866^2 + 5625^2 .

It is a cyclic number.

It is not a de Polignac number, because 78782581 - 2⁹ = 78782069 is a prime.

It is a super-2 number, since 2×78782581² = 12413390138043122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78782881) 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, 39391290 + 39391291.

It is an arithmetic number, because the mean of its divisors is an integer number (39391291).

Almost surely, 2^78782581 is an apocalyptic number.

It is an amenable number.

78782581 is a deficient number, since it is larger than the sum of its proper divisors (1).

78782581 is an equidigital number, since it uses as much as digits as its factorization.

78782581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 250880, while the sum is 46.

The square root of 78782581 is about 8875.9552162007. The cubic root of 78782581 is about 428.6900480281.

The spelling of 78782581 in words is "seventy-eight million, seven hundred eighty-two thousand, five hundred eighty-one".