78185649757 has 2 divisors, whose sum is σ = 78185649758. Its totient is φ = 78185649756.

The previous prime is 78185649697. The next prime is 78185649779. The reversal of 78185649757 is 75794658187.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66553164441 + 11632485316 = 257979^2 + 107854^2 .

It is a cyclic number.

It is not a de Polignac number, because 78185649757 - 2¹⁵ = 78185616989 is a prime.

It is a super-2 number, since 2×78185649757² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78185649692 and 78185649701.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78185629757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39092824878 + 39092824879.

It is an arithmetic number, because the mean of its divisors is an integer number (39092824879).

Almost surely, 2^78185649757 is an apocalyptic number.

It is an amenable number.

78185649757 is a deficient number, since it is larger than the sum of its proper divisors (1).

78185649757 is an equidigital number, since it uses as much as digits as its factorization.

78185649757 is an evil number, because the sum of its binary digits is even.

The product of its digits is 118540800, while the sum is 67.

The spelling of 78185649757 in words is "seventy-eight billion, one hundred eighty-five million, six hundred forty-nine thousand, seven hundred fifty-seven".