5661115991 has 4 divisors (see below), whose sum is σ = 5994122832. Its totient is φ = 5328109152.

The previous prime is 5661115963. The next prime is 5661116009. The reversal of 5661115991 is 1995111665.

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 5661115991 - 2⁶ = 5661115927 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 (5661115931) 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, 166503395 + ... + 166503428.

It is an arithmetic number, because the mean of its divisors is an integer number (1498530708).

Almost surely, 2^5661115991 is an apocalyptic number.

5661115991 is a deficient number, since it is larger than the sum of its proper divisors (333006841).

5661115991 is a wasteful number, since it uses less digits than its factorization.

5661115991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333006840.

The product of its digits is 72900, while the sum is 44.

The square root of 5661115991 is about 75240.3880306315. The cubic root of 5661115991 is about 1782.2447787799.

The spelling of 5661115991 in words is "five billion, six hundred sixty-one million, one hundred fifteen thousand, nine hundred ninety-one".