78191923 has 2 divisors, whose sum is σ = 78191924. Its totient is φ = 78191922.

The previous prime is 78191921. The next prime is 78191947. The reversal of 78191923 is 32919187.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78191923 - 2¹ = 78191921 is a prime.

It is a super-2 number, since 2×78191923² = 12227953644875858, which contains 22 as substring.

Together with 78191921, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (78191921) by changing a digit.

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

It is an upside-down number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39095961 + 39095962.

It is an arithmetic number, because the mean of its divisors is an integer number (39095962).

Almost surely, 2^78191923 is an apocalyptic number.

78191923 is a deficient number, since it is larger than the sum of its proper divisors (1).

78191923 is an equidigital number, since it uses as much as digits as its factorization.

78191923 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 40.

The square root of 78191923 is about 8842.6196910192. The cubic root of 78191923 is about 427.6160176663.

The spelling of 78191923 in words is "seventy-eight million, one hundred ninety-one thousand, nine hundred twenty-three".