2591681 has 2 divisors, whose sum is σ = 2591682. Its totient is φ = 2591680.

The previous prime is 2591669. The next prime is 2591683. The reversal of 2591681 is 1861952.

2591681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1478656 + 1113025 = 1216^2 + 1055^2 .

It is a cyclic number.

It is not a de Polignac number, because 2591681 - 2¹⁴ = 2575297 is a prime.

It is a super-2 number, since 2×2591681² = 13433620811522, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 2591683, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (2591683) 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 as a sum of consecutive naturals, namely, 1295840 + 1295841.

It is an arithmetic number, because the mean of its divisors is an integer number (1295841).

2^2591681 is an apocalyptic number.

It is an amenable number.

2591681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2591681 is an equidigital number, since it uses as much as digits as its factorization.

2591681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 32.

The square root of 2591681 is about 1609.8698705175. The cubic root of 2591681 is about 137.3600736307.

The spelling of 2591681 in words is "two million, five hundred ninety-one thousand, six hundred eighty-one".