78443649 has 6 divisors (see below), whose sum is σ = 113307506. Its totient is φ = 52295760.

The previous prime is 78443641. The next prime is 78443689. The reversal of 78443649 is 94634487.

It can be written as a sum of positive squares in only one way, i.e., 77792400 + 651249 = 8820^2 + 807^2 .

It is not a de Polignac number, because 78443649 - 2³ = 78443641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78443641) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4357972 + ... + 4357989.

Almost surely, 2^78443649 is an apocalyptic number.

It is an amenable number.

78443649 is a deficient number, since it is larger than the sum of its proper divisors (34863857).

78443649 is a wasteful number, since it uses less digits than its factorization.

78443649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8715967 (or 8715964 counting only the distinct ones).

The product of its digits is 580608, while the sum is 45.

The square root of 78443649 is about 8856.8419315239. The cubic root of 78443649 is about 428.0744058634.

The spelling of 78443649 in words is "seventy-eight million, four hundred forty-three thousand, six hundred forty-nine".