78328729 has 4 divisors (see below), whose sum is σ = 78382080. Its totient is φ = 78275380.

The previous prime is 78328727. The next prime is 78328751. The reversal of 78328729 is 92782387.

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 78328729 - 2¹ = 78328727 is a prime.

It is a super-2 number, since 2×78328729² = 12270779573510882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78328721) 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, 24409 + ... + 27430.

It is an arithmetic number, because the mean of its divisors is an integer number (19595520).

Almost surely, 2^78328729 is an apocalyptic number.

It is an amenable number.

78328729 is a deficient number, since it is larger than the sum of its proper divisors (53351).

78328729 is a wasteful number, since it uses less digits than its factorization.

78328729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53350.

The product of its digits is 338688, while the sum is 46.

The square root of 78328729 is about 8850.3519139072. The cubic root of 78328729 is about 427.8652605974.

It can be divided in two parts, 7832 and 8729, that added together give a palindrome (16561).

The spelling of 78328729 in words is "seventy-eight million, three hundred twenty-eight thousand, seven hundred twenty-nine".