78771289 has 2 divisors, whose sum is σ = 78771290. Its totient is φ = 78771288.

The previous prime is 78771281. The next prime is 78771311. The reversal of 78771289 is 98217787.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 43665664 + 35105625 = 6608^2 + 5925^2 .

It is a cyclic number.

It is not a de Polignac number, because 78771289 - 2³ = 78771281 is a prime.

It is not a weakly prime, because it can be changed into another prime (78771281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39385644 + 39385645.

It is an arithmetic number, because the mean of its divisors is an integer number (39385645).

Almost surely, 2^78771289 is an apocalyptic number.

It is an amenable number.

78771289 is a deficient number, since it is larger than the sum of its proper divisors (1).

78771289 is an equidigital number, since it uses as much as digits as its factorization.

78771289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 395136, while the sum is 49.

The square root of 78771289 is about 8875.3190928552. The cubic root of 78771289 is about 428.6695654998.

The spelling of 78771289 in words is "seventy-eight million, seven hundred seventy-one thousand, two hundred eighty-nine".