78082561 has 2 divisors, whose sum is σ = 78082562. Its totient is φ = 78082560.

The previous prime is 78082507. The next prime is 78082567. The reversal of 78082561 is 16528087.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55577025 + 22505536 = 7455^2 + 4744^2 .

It is an emirp because it is prime and its reverse (16528087) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78082561 - 2²¹ = 75985409 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78082561.

It is not a weakly prime, because it can be changed into another prime (78082567) 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, 39041280 + 39041281.

It is an arithmetic number, because the mean of its divisors is an integer number (39041281).

Almost surely, 2^78082561 is an apocalyptic number.

It is an amenable number.

78082561 is a deficient number, since it is larger than the sum of its proper divisors (1).

78082561 is an equidigital number, since it uses as much as digits as its factorization.

78082561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 78082561 is about 8836.4337263401. The cubic root of 78082561 is about 427.4165650014.

The spelling of 78082561 in words is "seventy-eight million, eighty-two thousand, five hundred sixty-one".