78972717178477 has 2 divisors, whose sum is σ = 78972717178478. Its totient is φ = 78972717178476.

The previous prime is 78972717178463. The next prime is 78972717178561. The reversal of 78972717178477 is 77487171727987.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77859905278276 + 1112811900201 = 8823826^2 + 1054899^2 .

It is a cyclic number.

It is not a de Polignac number, because 78972717178477 - 2²³ = 78972708789869 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78972717178477.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78972717178447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39486358589238 + 39486358589239.

It is an arithmetic number, because the mean of its divisors is an integer number (39486358589239).

Almost surely, 2^{78972717178477} is an apocalyptic number.

It is an amenable number.

78972717178477 is a deficient number, since it is larger than the sum of its proper divisors (1).

78972717178477 is an equidigital number, since it uses as much as digits as its factorization.

78972717178477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3794886144, while the sum is 82.

The spelling of 78972717178477 in words is "seventy-eight trillion, nine hundred seventy-two billion, seven hundred seventeen million, one hundred seventy-eight thousand, four hundred seventy-seven".