2779991 has 2 divisors, whose sum is σ = 2779992. Its totient is φ = 2779990.

The previous prime is 2779981. The next prime is 2780039. The reversal of 2779991 is 1999772.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2779991 - 2¹⁰ = 2778967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2779961) 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, 1389995 + 1389996.

It is an arithmetic number, because the mean of its divisors is an integer number (1389996).

2^2779991 is an apocalyptic number.

2779991 is a deficient number, since it is larger than the sum of its proper divisors (1).

2779991 is an equidigital number, since it uses as much as digits as its factorization.

2779991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 71442, while the sum is 44.

The square root of 2779991 is about 1667.3305011305. The cubic root of 2779991 is about 140.6094350509.

The spelling of 2779991 in words is "two million, seven hundred seventy-nine thousand, nine hundred ninety-one".