78215579 has 4 divisors (see below), whose sum is σ = 84232176. Its totient is φ = 72198984.

The previous prime is 78215563. The next prime is 78215587. The reversal of 78215579 is 97551287.

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

It is not a de Polignac number, because 78215579 - 2⁴ = 78215563 is a prime.

It is a super-2 number, since 2×78215579² = 12235353596610482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78215519) 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, 3008279 + ... + 3008304.

It is an arithmetic number, because the mean of its divisors is an integer number (21058044).

Almost surely, 2^78215579 is an apocalyptic number.

78215579 is a deficient number, since it is larger than the sum of its proper divisors (6016597).

78215579 is a wasteful number, since it uses less digits than its factorization.

78215579 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6016596.

The product of its digits is 176400, while the sum is 44.

The square root of 78215579 is about 8843.9572025197. The cubic root of 78215579 is about 427.6591366321.

It can be divided in two parts, 782 and 15579, that added together give a palindrome (16361).

The spelling of 78215579 in words is "seventy-eight million, two hundred fifteen thousand, five hundred seventy-nine".