78693641 has 4 divisors (see below), whose sum is σ = 84747012. Its totient is φ = 72640272.

The previous prime is 78693619. The next prime is 78693673. The reversal of 78693641 is 14639687.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6375625 + 72318016 = 2525^2 + 8504^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78693641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78693592 and 78693601.

It is not an unprimeable number, because it can be changed into a prime (78693691) 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, 3026666 + ... + 3026691.

It is an arithmetic number, because the mean of its divisors is an integer number (21186753).

Almost surely, 2^78693641 is an apocalyptic number.

It is an amenable number.

78693641 is a deficient number, since it is larger than the sum of its proper divisors (6053371).

78693641 is a wasteful number, since it uses less digits than its factorization.

78693641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6053370.

The product of its digits is 217728, while the sum is 44.

The square root of 78693641 is about 8870.9436363895. The cubic root of 78693641 is about 428.5286669663.

The spelling of 78693641 in words is "seventy-eight million, six hundred ninety-three thousand, six hundred forty-one".