78688638761 has 2 divisors, whose sum is σ = 78688638762. Its totient is φ = 78688638760.

The previous prime is 78688638737. The next prime is 78688638767. The reversal of 78688638761 is 16783688687.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70945518736 + 7743120025 = 266356^2 + 87995^2 .

It is a cyclic number.

It is not a de Polignac number, because 78688638761 - 2²² = 78684444457 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 78688638691 and 78688638700.

It is not a weakly prime, because it can be changed into another prime (78688638767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39344319380 + 39344319381.

It is an arithmetic number, because the mean of its divisors is an integer number (39344319381).

Almost surely, 2^78688638761 is an apocalyptic number.

It is an amenable number.

78688638761 is a deficient number, since it is larger than the sum of its proper divisors (1).

78688638761 is an equidigital number, since it uses as much as digits as its factorization.

78688638761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 130056192, while the sum is 68.

The spelling of 78688638761 in words is "seventy-eight billion, six hundred eighty-eight million, six hundred thirty-eight thousand, seven hundred sixty-one".