78777255457 has 2 divisors, whose sum is σ = 78777255458. Its totient is φ = 78777255456.

The previous prime is 78777255419. The next prime is 78777255461. The reversal of 78777255457 is 75455277787.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78267895696 + 509359761 = 279764^2 + 22569^2 .

It is a cyclic number.

It is not a de Polignac number, because 78777255457 - 2⁷ = 78777255329 is a prime.

It is not a weakly prime, because it can be changed into another prime (78777255257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39388627728 + 39388627729.

It is an arithmetic number, because the mean of its divisors is an integer number (39388627729).

Almost surely, 2^78777255457 is an apocalyptic number.

It is an amenable number.

78777255457 is a deficient number, since it is larger than the sum of its proper divisors (1).

78777255457 is an equidigital number, since it uses as much as digits as its factorization.

78777255457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 134456000, while the sum is 64.

The spelling of 78777255457 in words is "seventy-eight billion, seven hundred seventy-seven million, two hundred fifty-five thousand, four hundred fifty-seven".