78403321 has 2 divisors, whose sum is σ = 78403322. Its totient is φ = 78403320.

The previous prime is 78403289. The next prime is 78403331. The reversal of 78403321 is 12330487.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72590400 + 5812921 = 8520^2 + 2411^2 .

It is a cyclic number.

It is not a de Polignac number, because 78403321 - 2⁵ = 78403289 is a prime.

It is a super-2 number, since 2×78403321² = 12294161487658082, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78403321.

It is not a weakly prime, because it can be changed into another prime (78403331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39201660 + 39201661.

It is an arithmetic number, because the mean of its divisors is an integer number (39201661).

Almost surely, 2^78403321 is an apocalyptic number.

It is an amenable number.

78403321 is a deficient number, since it is larger than the sum of its proper divisors (1).

78403321 is an equidigital number, since it uses as much as digits as its factorization.

78403321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 78403321 is about 8854.5649808446. The cubic root of 78403321 is about 428.0010353863.

The spelling of 78403321 in words is "seventy-eight million, four hundred three thousand, three hundred twenty-one".