61561543 has 4 divisors (see below), whose sum is σ = 62480440. Its totient is φ = 60642648.

The previous prime is 61561529. The next prime is 61561561. The reversal of 61561543 is 34516516.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61561543 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61561583) 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, 459348 + ... + 459481.

It is an arithmetic number, because the mean of its divisors is an integer number (15620110).

Almost surely, 2^61561543 is an apocalyptic number.

61561543 is a deficient number, since it is larger than the sum of its proper divisors (918897).

61561543 is an equidigital number, since it uses as much as digits as its factorization.

61561543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 918896.

The product of its digits is 10800, while the sum is 31.

The square root of 61561543 is about 7846.1164278897. The cubic root of 61561543 is about 394.8539608612.

The spelling of 61561543 in words is "sixty-one million, five hundred sixty-one thousand, five hundred forty-three".