78487729 has 4 divisors (see below), whose sum is σ = 78517620. Its totient is φ = 78457840.

The previous prime is 78487699. The next prime is 78487757. The reversal of 78487729 is 92778487.

It is a happy number.

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 37847104 + 40640625 = 6152^2 + 6375^2 .

It is a cyclic number.

It is not a de Polignac number, because 78487729 - 2¹¹ = 78485681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78487429) 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, 10582 + ... + 16399.

It is an arithmetic number, because the mean of its divisors is an integer number (19629405).

Almost surely, 2^78487729 is an apocalyptic number.

It is an amenable number.

78487729 is a deficient number, since it is larger than the sum of its proper divisors (29891).

78487729 is a wasteful number, since it uses less digits than its factorization.

78487729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29890.

The product of its digits is 1580544, while the sum is 52.

The square root of 78487729 is about 8859.3300536779. The cubic root of 78487729 is about 428.1545737576.

The spelling of 78487729 in words is "seventy-eight million, four hundred eighty-seven thousand, seven hundred twenty-nine".