2491871 has 2 divisors, whose sum is σ = 2491872. Its totient is φ = 2491870.

The previous prime is 2491861. The next prime is 2491891. The reversal of 2491871 is 1781942.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2491871 - 2¹⁰ = 2490847 is a prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2491861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1245935 + 1245936.

It is an arithmetic number, because the mean of its divisors is an integer number (1245936).

2^2491871 is an apocalyptic number.

2491871 is a deficient number, since it is larger than the sum of its proper divisors (1).

2491871 is an equidigital number, since it uses as much as digits as its factorization.

2491871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 32.

The square root of 2491871 is about 1578.5661215166. The cubic root of 2491871 is about 135.5736177620.

The spelling of 2491871 in words is "two million, four hundred ninety-one thousand, eight hundred seventy-one".