678043561 has 4 divisors (see below), whose sum is σ = 730200772. Its totient is φ = 625886352.

The previous prime is 678043559. The next prime is 678043567. The reversal of 678043561 is 165340876.

It is a happy number.

678043561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 28558336 + 649485225 = 5344^2 + 25485^2 .

It is not a de Polignac number, because 678043561 - 2¹ = 678043559 is a prime.

It is a super-2 number, since 2×678043561² = 919486141227121442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (678043567) 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, 26078586 + ... + 26078611.

It is an arithmetic number, because the mean of its divisors is an integer number (182550193).

Almost surely, 2^678043561 is an apocalyptic number.

It is an amenable number.

678043561 is a deficient number, since it is larger than the sum of its proper divisors (52157211).

678043561 is a wasteful number, since it uses less digits than its factorization.

678043561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52157210.

The product of its (nonzero) digits is 120960, while the sum is 40.

The square root of 678043561 is about 26039.2695942110. The cubic root of 678043561 is about 878.5217783499.

The spelling of 678043561 in words is "six hundred seventy-eight million, forty-three thousand, five hundred sixty-one".