78451816 has 8 divisors (see below), whose sum is σ = 147097170. Its totient is φ = 39225904.

The previous prime is 78451811. The next prime is 78451831. The reversal of 78451816 is 61815487.

It can be written as a sum of positive squares in only one way, i.e., 61559716 + 16892100 = 7846^2 + 4110^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (78451811) 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, 4903231 + ... + 4903246.

Almost surely, 2^78451816 is an apocalyptic number.

It is an amenable number.

78451816 is a deficient number, since it is larger than the sum of its proper divisors (68645354).

78451816 is a wasteful number, since it uses less digits than its factorization.

78451816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9806483 (or 9806479 counting only the distinct ones).

The product of its digits is 53760, while the sum is 40.

The square root of 78451816 is about 8857.3029755112. The cubic root of 78451816 is about 428.0892613782.

The spelling of 78451816 in words is "seventy-eight million, four hundred fifty-one thousand, eight hundred sixteen".