78304991 has 2 divisors, whose sum is σ = 78304992. Its totient is φ = 78304990.

The previous prime is 78304979. The next prime is 78305011. The reversal of 78304991 is 19940387.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78304991 - 2²⁶ = 11196127 is a prime.

It is a super-2 number, since 2×78304991² = 12263343231020162, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78304921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39152495 + 39152496.

It is an arithmetic number, because the mean of its divisors is an integer number (39152496).

Almost surely, 2^78304991 is an apocalyptic number.

78304991 is a deficient number, since it is larger than the sum of its proper divisors (1).

78304991 is an equidigital number, since it uses as much as digits as its factorization.

78304991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54432, while the sum is 41.

The square root of 78304991 is about 8849.0107356698. The cubic root of 78304991 is about 427.8220338364.

It can be divided in two parts, 7830 and 4991, that added together give a palindrome (12821).

The spelling of 78304991 in words is "seventy-eight million, three hundred four thousand, nine hundred ninety-one".