78591993 has 4 divisors (see below), whose sum is σ = 104789328. Its totient is φ = 52394660.

The previous prime is 78591991. The next prime is 78592021. The reversal of 78591993 is 39919587.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 78591993 - 2¹ = 78591991 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78591991) 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, 13098663 + ... + 13098668.

It is an arithmetic number, because the mean of its divisors is an integer number (26197332).

Almost surely, 2^78591993 is an apocalyptic number.

It is an amenable number.

78591993 is a deficient number, since it is larger than the sum of its proper divisors (26197335).

78591993 is a wasteful number, since it uses less digits than its factorization.

78591993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26197334.

The product of its digits is 612360, while the sum is 51.

The square root of 78591993 is about 8865.2125186033. The cubic root of 78591993 is about 428.3440783522.

The spelling of 78591993 in words is "seventy-eight million, five hundred ninety-one thousand, nine hundred ninety-three".