605555991 has 6 divisors (see below), whose sum is σ = 874692000. Its totient is φ = 403703988.

The previous prime is 605555969. The next prime is 605556001. The reversal of 605555991 is 199555506.

605555991 is a `hidden beast` number, since 6 + 0 + 5 + 5 + 559 + 91 = 666.

It is not a de Polignac number, because 605555991 - 2⁵ = 605555959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (605555791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 33641991 + ... + 33642008.

It is an arithmetic number, because the mean of its divisors is an integer number (145782000).

Almost surely, 2^605555991 is an apocalyptic number.

605555991 is a deficient number, since it is larger than the sum of its proper divisors (269136009).

605555991 is a wasteful number, since it uses less digits than its factorization.

605555991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67284005 (or 67284002 counting only the distinct ones).

The product of its (nonzero) digits is 303750, while the sum is 45.

The square root of 605555991 is about 24608.0472813265. The cubic root of 605555991 is about 846.0280618762.

The spelling of 605555991 in words is "six hundred five million, five hundred fifty-five thousand, nine hundred ninety-one".