78197549 has 2 divisors, whose sum is σ = 78197550. Its totient is φ = 78197548.

The previous prime is 78197503. The next prime is 78197573. The reversal of 78197549 is 94579187.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68475625 + 9721924 = 8275^2 + 3118^2 .

It is an emirp because it is prime and its reverse (94579187) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78197549 - 2¹⁶ = 78132013 is a prime.

It is a super-2 number, since 2×78197549² = 12229713339214802, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 78197497 and 78197506.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78197579) 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, 39098774 + 39098775.

It is an arithmetic number, because the mean of its divisors is an integer number (39098775).

Almost surely, 2^78197549 is an apocalyptic number.

It is an amenable number.

78197549 is a deficient number, since it is larger than the sum of its proper divisors (1).

78197549 is an equidigital number, since it uses as much as digits as its factorization.

78197549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 635040, while the sum is 50.

The square root of 78197549 is about 8842.9378036940. The cubic root of 78197549 is about 427.6262732439.

The spelling of 78197549 in words is "seventy-eight million, one hundred ninety-seven thousand, five hundred forty-nine".