78847661 has 4 divisors (see below), whose sum is σ = 78921024. Its totient is φ = 78774300.

The previous prime is 78847651. The next prime is 78847673. The reversal of 78847661 is 16674887.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16674887 = 311 ⋅53617.

It is a cyclic number.

It is not a de Polignac number, because 78847661 - 2⁶ = 78847597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78847621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35045 + ... + 37226.

It is an arithmetic number, because the mean of its divisors is an integer number (19730256).

Almost surely, 2^78847661 is an apocalyptic number.

It is an amenable number.

78847661 is a deficient number, since it is larger than the sum of its proper divisors (73363).

78847661 is a wasteful number, since it uses less digits than its factorization.

78847661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73362.

The product of its digits is 451584, while the sum is 47.

The square root of 78847661 is about 8879.6205436944. The cubic root of 78847661 is about 428.8080583347.

The spelling of 78847661 in words is "seventy-eight million, eight hundred forty-seven thousand, six hundred sixty-one".