6111555561 has 48 divisors (see below), whose sum is σ = 9712035840. Its totient is φ = 3686173920.

The previous prime is 6111555503. The next prime is 6111555661. The reversal of 6111555561 is 1655551116.

It is a happy number.

It is not a de Polignac number, because 6111555561 - 2⁹ = 6111555049 is a prime.

It is a super-2 number, since 2×6111555561² = 74702222750380049442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (6111555361) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4604880 + ... + 4606206.

It is an arithmetic number, because the mean of its divisors is an integer number (202334080).

Almost surely, 2^6111555561 is an apocalyptic number.

It is an amenable number.

6111555561 is a deficient number, since it is larger than the sum of its proper divisors (3600480279).

6111555561 is a wasteful number, since it uses less digits than its factorization.

6111555561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2546 (or 2543 counting only the distinct ones).

The product of its digits is 22500, while the sum is 36.

The square root of 6111555561 is about 78176.4386564136. The cubic root of 6111555561 is about 1828.3131719485.

It can be divided in two parts, 6111555 and 561, that added together give a palindrome (6112116).

The spelling of 6111555561 in words is "six billion, one hundred eleven million, five hundred fifty-five thousand, five hundred sixty-one".