78193121 has 2 divisors, whose sum is σ = 78193122. Its totient is φ = 78193120.

The previous prime is 78193117. The next prime is 78193163. The reversal of 78193121 is 12139187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69072721 + 9120400 = 8311^2 + 3020^2 .

It is an emirp because it is prime and its reverse (12139187) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78193121 - 2² = 78193117 is a prime.

It is a super-2 number, since 2×78193121² = 12228328343441282, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78190121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39096560 + 39096561.

It is an arithmetic number, because the mean of its divisors is an integer number (39096561).

Almost surely, 2^78193121 is an apocalyptic number.

It is an amenable number.

78193121 is a deficient number, since it is larger than the sum of its proper divisors (1).

78193121 is an equidigital number, since it uses as much as digits as its factorization.

78193121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 32.

The square root of 78193121 is about 8842.6874308663. The cubic root of 78193121 is about 427.6182015294.

The spelling of 78193121 in words is "seventy-eight million, one hundred ninety-three thousand, one hundred twenty-one".