61686578 has 16 divisors (see below), whose sum is σ = 97632000. Its totient is φ = 29150352.

The previous prime is 61686551. The next prime is 61686589. The reversal of 61686578 is 87568616.

61686578 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 16508 + ... + 19896.

It is an arithmetic number, because the mean of its divisors is an integer number (6102000).

Almost surely, 2^61686578 is an apocalyptic number.

61686578 is a deficient number, since it is larger than the sum of its proper divisors (35945422).

61686578 is a wasteful number, since it uses less digits than its factorization.

61686578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3889.

The product of its digits is 483840, while the sum is 47.

The square root of 61686578 is about 7854.0803408165. The cubic root of 61686578 is about 395.1211037096.

The spelling of 61686578 in words is "sixty-one million, six hundred eighty-six thousand, five hundred seventy-eight".