78919081 has 2 divisors, whose sum is σ = 78919082. Its totient is φ = 78919080.

The previous prime is 78919079. The next prime is 78919097. The reversal of 78919081 is 18091987.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75533481 + 3385600 = 8691^2 + 1840^2 .

It is a cyclic number.

It is not a de Polignac number, because 78919081 - 2¹ = 78919079 is a prime.

It is a super-2 number, since 2×78919081² = 12456442691769122, which contains 22 as substring.

Together with 78919079, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (78919381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39459540 + 39459541.

It is an arithmetic number, because the mean of its divisors is an integer number (39459541).

Almost surely, 2^78919081 is an apocalyptic number.

It is an amenable number.

78919081 is a deficient number, since it is larger than the sum of its proper divisors (1).

78919081 is an equidigital number, since it uses as much as digits as its factorization.

78919081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 43.

The square root of 78919081 is about 8883.6412016695. The cubic root of 78919081 is about 428.9374903261.

The spelling of 78919081 in words is "seventy-eight million, nine hundred nineteen thousand, eighty-one".