78617561 has 8 divisors (see below), whose sum is σ = 86851200. Its totient is φ = 70565040.

The previous prime is 78617551. The next prime is 78617597. The reversal of 78617561 is 16571687.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78617561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78617551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44366 + ... + 46103.

It is an arithmetic number, because the mean of its divisors is an integer number (10856400).

Almost surely, 2^78617561 is an apocalyptic number.

It is an amenable number.

78617561 is a deficient number, since it is larger than the sum of its proper divisors (8233639).

78617561 is a wasteful number, since it uses less digits than its factorization.

78617561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90559.

The product of its digits is 70560, while the sum is 41.

The square root of 78617561 is about 8866.6544423475. The cubic root of 78617561 is about 428.3905237705.

The spelling of 78617561 in words is "seventy-eight million, six hundred seventeen thousand, five hundred sixty-one".