78775321 has 2 divisors, whose sum is σ = 78775322. Its totient is φ = 78775320.

The previous prime is 78775303. The next prime is 78775343. The reversal of 78775321 is 12357787.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47817225 + 30958096 = 6915^2 + 5564^2 .

It is a cyclic number.

It is not a de Polignac number, because 78775321 - 2⁵ = 78775289 is a prime.

It is not a weakly prime, because it can be changed into another prime (78775381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39387660 + 39387661.

It is an arithmetic number, because the mean of its divisors is an integer number (39387661).

Almost surely, 2^78775321 is an apocalyptic number.

It is an amenable number.

78775321 is a deficient number, since it is larger than the sum of its proper divisors (1).

78775321 is an equidigital number, since it uses as much as digits as its factorization.

78775321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82320, while the sum is 40.

The square root of 78775321 is about 8875.5462367113. The cubic root of 78775321 is about 428.6768793584.

The spelling of 78775321 in words is "seventy-eight million, seven hundred seventy-five thousand, three hundred twenty-one".