78821599 has 2 divisors, whose sum is σ = 78821600. Its totient is φ = 78821598.

The previous prime is 78821593. The next prime is 78821629. The reversal of 78821599 is 99512887.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78821599 - 2¹⁹ = 78297311 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78821593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39410799 + 39410800.

It is an arithmetic number, because the mean of its divisors is an integer number (39410800).

Almost surely, 2^78821599 is an apocalyptic number.

78821599 is a deficient number, since it is larger than the sum of its proper divisors (1).

78821599 is an equidigital number, since it uses as much as digits as its factorization.

78821599 is an evil number, because the sum of its binary digits is even.

The product of its digits is 362880, while the sum is 49.

The square root of 78821599 is about 8878.1529047432. The cubic root of 78821599 is about 428.7608076109.

The spelling of 78821599 in words is "seventy-eight million, eight hundred twenty-one thousand, five hundred ninety-nine".