2611991 has 2 divisors, whose sum is σ = 2611992. Its totient is φ = 2611990.

The previous prime is 2611981. The next prime is 2611997. The reversal of 2611991 is 1991162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2611991 - 2¹⁰ = 2610967 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2611997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1305995 + 1305996.

It is an arithmetic number, because the mean of its divisors is an integer number (1305996).

2^2611991 is an apocalyptic number.

2611991 is a deficient number, since it is larger than the sum of its proper divisors (1).

2611991 is an equidigital number, since it uses as much as digits as its factorization.

2611991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 972, while the sum is 29.

The square root of 2611991 is about 1616.1655237011. The cubic root of 2611991 is about 137.7179529601.

The spelling of 2611991 in words is "two million, six hundred eleven thousand, nine hundred ninety-one".