61565555 has 4 divisors (see below), whose sum is σ = 73878672. Its totient is φ = 49252440.

The previous prime is 61565527. The next prime is 61565587. The reversal of 61565555 is 55556516.

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

It is a de Polignac number, because none of the positive numbers 2^k-61565555 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6156551 + ... + 6156560.

It is an arithmetic number, because the mean of its divisors is an integer number (18469668).

Almost surely, 2^61565555 is an apocalyptic number.

61565555 is a deficient number, since it is larger than the sum of its proper divisors (12313117).

61565555 is a wasteful number, since it uses less digits than its factorization.

61565555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12313116.

The product of its digits is 112500, while the sum is 38.

The square root of 61565555 is about 7846.3720916102. The cubic root of 61565555 is about 394.8625382923.

It can be divided in two parts, 6156 and 5555, that added together give a palindrome (11711).

The spelling of 61565555 in words is "sixty-one million, five hundred sixty-five thousand, five hundred fifty-five".