78061691 has 2 divisors, whose sum is σ = 78061692. Its totient is φ = 78061690.

The previous prime is 78061681. The next prime is 78061699. The reversal of 78061691 is 19616087.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78061691 - 2¹⁰ = 78060667 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78061699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39030845 + 39030846.

It is an arithmetic number, because the mean of its divisors is an integer number (39030846).

Almost surely, 2^78061691 is an apocalyptic number.

78061691 is a deficient number, since it is larger than the sum of its proper divisors (1).

78061691 is an equidigital number, since it uses as much as digits as its factorization.

78061691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 78061691 is about 8835.2527411501. The cubic root of 78061691 is about 427.3784814718.

The spelling of 78061691 in words is "seventy-eight million, sixty-one thousand, six hundred ninety-one".