78655171561 has 2 divisors, whose sum is σ = 78655171562. Its totient is φ = 78655171560.

The previous prime is 78655171513. The next prime is 78655171601. The reversal of 78655171561 is 16517155687.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46885673961 + 31769497600 = 216531^2 + 178240^2 .

It is a cyclic number.

It is not a de Polignac number, because 78655171561 - 2¹³ = 78655163369 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 78655171499 and 78655171508.

It is not a weakly prime, because it can be changed into another prime (78655171061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39327585780 + 39327585781.

It is an arithmetic number, because the mean of its divisors is an integer number (39327585781).

Almost surely, 2^78655171561 is an apocalyptic number.

It is an amenable number.

78655171561 is a deficient number, since it is larger than the sum of its proper divisors (1).

78655171561 is an equidigital number, since it uses as much as digits as its factorization.

78655171561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1764000, while the sum is 52.

The spelling of 78655171561 in words is "seventy-eight billion, six hundred fifty-five million, one hundred seventy-one thousand, five hundred sixty-one".