78821593 has 2 divisors, whose sum is σ = 78821594. Its totient is φ = 78821592.

The previous prime is 78821579. The next prime is 78821599. The reversal of 78821593 is 39512887.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43917129 + 34904464 = 6627^2 + 5908^2 .

It is a cyclic number.

It is not a de Polignac number, because 78821593 - 2²¹ = 76724441 is a prime.

It is not a weakly prime, because it can be changed into another prime (78821599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39410796 + 39410797.

It is an arithmetic number, because the mean of its divisors is an integer number (39410797).

Almost surely, 2^78821593 is an apocalyptic number.

It is an amenable number.

78821593 is a deficient number, since it is larger than the sum of its proper divisors (1).

78821593 is an equidigital number, since it uses as much as digits as its factorization.

78821593 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 43.

The square root of 78821593 is about 8878.1525668351. The cubic root of 78821593 is about 428.7607967316.

The spelling of 78821593 in words is "seventy-eight million, eight hundred twenty-one thousand, five hundred ninety-three".