78521315 has 4 divisors (see below), whose sum is σ = 94225584. Its totient is φ = 62817048.

The previous prime is 78521309. The next prime is 78521323. The reversal of 78521315 is 51312587.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 51312587 = 167 ⋅307261.

It is a cyclic number.

It is not a de Polignac number, because 78521315 - 2¹⁴ = 78504931 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7852127 + ... + 7852136.

It is an arithmetic number, because the mean of its divisors is an integer number (23556396).

Almost surely, 2^78521315 is an apocalyptic number.

78521315 is a deficient number, since it is larger than the sum of its proper divisors (15704269).

78521315 is a wasteful number, since it uses less digits than its factorization.

78521315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15704268.

The product of its digits is 8400, while the sum is 32.

The square root of 78521315 is about 8861.2253667312. The cubic root of 78521315 is about 428.2156361642.

The spelling of 78521315 in words is "seventy-eight million, five hundred twenty-one thousand, three hundred fifteen".