78578521 has 16 divisors (see below), whose sum is σ = 93127680. Its totient is φ = 64880640.

The previous prime is 78578483. The next prime is 78578527. The reversal of 78578521 is 12587587.

It is a cyclic number.

It is not a de Polignac number, because 78578521 - 2⁷ = 78578393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78578527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55065 + ... + 56473.

It is an arithmetic number, because the mean of its divisors is an integer number (5820480).

Almost surely, 2^78578521 is an apocalyptic number.

It is an amenable number.

78578521 is a deficient number, since it is larger than the sum of its proper divisors (14549159).

78578521 is a wasteful number, since it uses less digits than its factorization.

78578521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1704.

The product of its digits is 156800, while the sum is 43.

The square root of 78578521 is about 8864.4526621783. The cubic root of 78578521 is about 428.3196018080.

The spelling of 78578521 in words is "seventy-eight million, five hundred seventy-eight thousand, five hundred twenty-one".