78155249 has 2 divisors, whose sum is σ = 78155250. Its totient is φ = 78155248.

The previous prime is 78155237. The next prime is 78155269. The reversal of 78155249 is 94255187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51940849 + 26214400 = 7207^2 + 5120^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78155249 is a prime.

It is a super-2 number, since 2×78155249² = 12216485892504002, which contains 22 as substring.

It is a Chen prime.

It is equal to p_4568099 and since 78155249 and 4568099 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (78155269) 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, 39077624 + 39077625.

It is an arithmetic number, because the mean of its divisors is an integer number (39077625).

Almost surely, 2^78155249 is an apocalyptic number.

It is an amenable number.

78155249 is a deficient number, since it is larger than the sum of its proper divisors (1).

78155249 is an equidigital number, since it uses as much as digits as its factorization.

78155249 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 100800, while the sum is 41.

The square root of 78155249 is about 8840.5457410728. The cubic root of 78155249 is about 427.5491529498.

The spelling of 78155249 in words is "seventy-eight million, one hundred fifty-five thousand, two hundred forty-nine".