78589891 has 4 divisors (see below), whose sum is σ = 78621192. Its totient is φ = 78558592.

The previous prime is 78589879. The next prime is 78589943. The reversal of 78589891 is 19898587.

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

It is a cyclic number.

It is not a de Polignac number, because 78589891 - 2¹⁵ = 78557123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78587891) 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, 11521 + ... + 17026.

It is an arithmetic number, because the mean of its divisors is an integer number (19655298).

Almost surely, 2^78589891 is an apocalyptic number.

78589891 is a deficient number, since it is larger than the sum of its proper divisors (31301).

78589891 is a wasteful number, since it uses less digits than its factorization.

78589891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31300.

The product of its digits is 1451520, while the sum is 55.

The square root of 78589891 is about 8865.0939645330. The cubic root of 78589891 is about 428.3402595269.

The spelling of 78589891 in words is "seventy-eight million, five hundred eighty-nine thousand, eight hundred ninety-one".