61539561 has 8 divisors (see below), whose sum is σ = 91169760. Its totient is φ = 41026356.

The previous prime is 61539553. The next prime is 61539581. The reversal of 61539561 is 16593516.

61539561 is a `hidden beast` number, since 61 + 5 + 39 + 561 = 666.

61539561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 61539561 - 2³ = 61539553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61539521) 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 7 ways as a sum of consecutive naturals, for example, 1139595 + ... + 1139648.

It is an arithmetic number, because the mean of its divisors is an integer number (11396220).

Almost surely, 2^61539561 is an apocalyptic number.

It is an amenable number.

61539561 is a deficient number, since it is larger than the sum of its proper divisors (29630199).

61539561 is a wasteful number, since it uses less digits than its factorization.

61539561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2279252 (or 2279246 counting only the distinct ones).

The product of its digits is 24300, while the sum is 36.

The square root of 61539561 is about 7844.7154824123. The cubic root of 61539561 is about 394.8069579616.

The spelling of 61539561 in words is "sixty-one million, five hundred thirty-nine thousand, five hundred sixty-one".