78555601 has 2 divisors, whose sum is σ = 78555602. Its totient is φ = 78555600.

The previous prime is 78555569. The next prime is 78555611. The reversal of 78555601 is 10655587.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62031376 + 16524225 = 7876^2 + 4065^2 .

It is an emirp because it is prime and its reverse (10655587) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78555601 - 2⁵ = 78555569 is a prime.

It is not a weakly prime, because it can be changed into another prime (78555611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39277800 + 39277801.

It is an arithmetic number, because the mean of its divisors is an integer number (39277801).

Almost surely, 2^78555601 is an apocalyptic number.

It is an amenable number.

78555601 is a deficient number, since it is larger than the sum of its proper divisors (1).

78555601 is an equidigital number, since it uses as much as digits as its factorization.

78555601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42000, while the sum is 37.

The square root of 78555601 is about 8863.1597638765. The cubic root of 78555601 is about 428.2779532769.

It can be divided in two parts, 7855 and 5601, that added together give a square (13456 = 116²).

The spelling of 78555601 in words is "seventy-eight million, five hundred fifty-five thousand, six hundred one".