78729089 has 4 divisors (see below), whose sum is σ = 80404224. Its totient is φ = 77053956.

The previous prime is 78729083. The next prime is 78729121. The reversal of 78729089 is 98092787.

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 78729089 - 2⁴ = 78729073 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (78729083) 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, 837497 + ... + 837590.

It is an arithmetic number, because the mean of its divisors is an integer number (20101056).

Almost surely, 2^78729089 is an apocalyptic number.

It is an amenable number.

78729089 is a deficient number, since it is larger than the sum of its proper divisors (1675135).

78729089 is a wasteful number, since it uses less digits than its factorization.

78729089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1675134.

The product of its (nonzero) digits is 508032, while the sum is 50.

The square root of 78729089 is about 8872.9413950505. The cubic root of 78729089 is about 428.5930017024.

It can be divided in two parts, 7872 and 9089, that added together give a palindrome (16961).

The spelling of 78729089 in words is "seventy-eight million, seven hundred twenty-nine thousand, eighty-nine".