78404171 has 4 divisors (see below), whose sum is σ = 81813072. Its totient is φ = 74995272.

The previous prime is 78404149. The next prime is 78404173. The reversal of 78404171 is 17140487.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-78404171 is a prime.

It is a super-2 number, since 2×78404171² = 12294428060394482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78404173) 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 3 ways as a sum of consecutive naturals, for example, 1704416 + ... + 1704461.

It is an arithmetic number, because the mean of its divisors is an integer number (20453268).

Almost surely, 2^78404171 is an apocalyptic number.

78404171 is a deficient number, since it is larger than the sum of its proper divisors (3408901).

78404171 is a wasteful number, since it uses less digits than its factorization.

78404171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3408900.

The product of its (nonzero) digits is 6272, while the sum is 32.

The square root of 78404171 is about 8854.6129785553. The cubic root of 78404171 is about 428.0025820877.

The spelling of 78404171 in words is "seventy-eight million, four hundred four thousand, one hundred seventy-one".