78909155 has 16 divisors (see below), whose sum is σ = 107974944. Its totient is φ = 54842880.

The previous prime is 78909151. The next prime is 78909157. The reversal of 78909155 is 55190987.

It is a happy number.

It is not a de Polignac number, because 78909155 - 2² = 78909151 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78909151) 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 in 15 ways as a sum of consecutive naturals, for example, 34601 + ... + 36810.

It is an arithmetic number, because the mean of its divisors is an integer number (6748434).

Almost surely, 2^78909155 is an apocalyptic number.

78909155 is a deficient number, since it is larger than the sum of its proper divisors (29065789).

78909155 is a wasteful number, since it uses less digits than its factorization.

78909155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71446.

The product of its (nonzero) digits is 113400, while the sum is 44.

The square root of 78909155 is about 8883.0825167844. The cubic root of 78909155 is about 428.9195064538.

The spelling of 78909155 in words is "seventy-eight million, nine hundred nine thousand, one hundred fifty-five".