78821293 has 2 divisors, whose sum is σ = 78821294. Its totient is φ = 78821292.

The previous prime is 78821273. The next prime is 78821317. The reversal of 78821293 is 39212887.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78801129 + 20164 = 8877^2 + 142^2 .

It is a cyclic number.

It is not a de Polignac number, because 78821293 - 2⁵ = 78821261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78821203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39410646 + 39410647.

It is an arithmetic number, because the mean of its divisors is an integer number (39410647).

Almost surely, 2^78821293 is an apocalyptic number.

It is an amenable number.

78821293 is a deficient number, since it is larger than the sum of its proper divisors (1).

78821293 is an equidigital number, since it uses as much as digits as its factorization.

78821293 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 40.

The square root of 78821293 is about 8878.1356714121. The cubic root of 78821293 is about 428.7602527673.

The spelling of 78821293 in words is "seventy-eight million, eight hundred twenty-one thousand, two hundred ninety-three".