61535561 has 4 divisors (see below), whose sum is σ = 61551252. Its totient is φ = 61519872.

The previous prime is 61535531. The next prime is 61535609. The reversal of 61535561 is 16553516.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 61152400 + 383161 = 7820^2 + 619^2 .

It is a cyclic number.

It is not a de Polignac number, because 61535561 - 2⁶ = 61535497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61535501) 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, 3785 + ... + 11721.

It is an arithmetic number, because the mean of its divisors is an integer number (15387813).

Almost surely, 2^61535561 is an apocalyptic number.

It is an amenable number.

61535561 is a deficient number, since it is larger than the sum of its proper divisors (15691).

61535561 is an equidigital number, since it uses as much as digits as its factorization.

61535561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15690.

The product of its digits is 13500, while the sum is 32.

The square root of 61535561 is about 7844.4605295712. The cubic root of 61535561 is about 394.7984037784.

The spelling of 61535561 in words is "sixty-one million, five hundred thirty-five thousand, five hundred sixty-one".