611660561 has 4 divisors (see below), whose sum is σ = 647640612. Its totient is φ = 575680512.

The previous prime is 611660557. The next prime is 611660573. The reversal of 611660561 is 165066116.

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 225930961 + 385729600 = 15031^2 + 19640^2 .

It is a cyclic number.

It is not a de Polignac number, because 611660561 - 2² = 611660557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (611660261) 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 3 ways as a sum of consecutive naturals, for example, 17990000 + ... + 17990033.

It is an arithmetic number, because the mean of its divisors is an integer number (161910153).

Almost surely, 2^611660561 is an apocalyptic number.

It is an amenable number.

611660561 is a deficient number, since it is larger than the sum of its proper divisors (35980051).

611660561 is a wasteful number, since it uses less digits than its factorization.

611660561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35980050.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 611660561 is about 24731.7722979976. The cubic root of 611660561 is about 848.8614796276.

The spelling of 611660561 in words is "six hundred eleven million, six hundred sixty thousand, five hundred sixty-one".