61557539 has 4 divisors (see below), whose sum is σ = 62719056. Its totient is φ = 60396024.

The previous prime is 61557533. The next prime is 61557547. The reversal of 61557539 is 93575516.

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

It is a cyclic number.

It is not a de Polignac number, because 61557539 - 2²⁰ = 60508963 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 61557496 and 61557505.

It is not an unprimeable number, because it can be changed into a prime (61557533) 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, 580679 + ... + 580784.

It is an arithmetic number, because the mean of its divisors is an integer number (15679764).

Almost surely, 2^61557539 is an apocalyptic number.

61557539 is a deficient number, since it is larger than the sum of its proper divisors (1161517).

61557539 is a wasteful number, since it uses less digits than its factorization.

61557539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1161516.

The product of its digits is 141750, while the sum is 41.

The square root of 61557539 is about 7845.8612656610. The cubic root of 61557539 is about 394.8454001621.

The spelling of 61557539 in words is "sixty-one million, five hundred fifty-seven thousand, five hundred thirty-nine".