2605991 has 2 divisors, whose sum is σ = 2605992. Its totient is φ = 2605990.

The previous prime is 2605987. The next prime is 2606011. The reversal of 2605991 is 1995062.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2605991 - 2² = 2605987 is a prime.

It is a super-3 number, since 3×2605991³ = 53093332959783771813, which contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2605931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1302995 + 1302996.

It is an arithmetic number, because the mean of its divisors is an integer number (1302996).

2^2605991 is an apocalyptic number.

2605991 is a deficient number, since it is larger than the sum of its proper divisors (1).

2605991 is an equidigital number, since it uses as much as digits as its factorization.

2605991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4860, while the sum is 32.

The square root of 2605991 is about 1614.3082109684. The cubic root of 2605991 is about 137.6124215564.

The spelling of 2605991 in words is "two million, six hundred five thousand, nine hundred ninety-one".