2605781 has 2 divisors, whose sum is σ = 2605782. Its totient is φ = 2605780.

The previous prime is 2605769. The next prime is 2605787. The reversal of 2605781 is 1875062.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2588881 + 16900 = 1609^2 + 130^2 .

It is a cyclic number.

It is not a de Polignac number, because 2605781 - 2¹⁴ = 2589397 is a prime.

It is a super-2 number, since 2×2605781² = 13580189239922, which contains 22 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 (2605787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1302890 + 1302891.

It is an arithmetic number, because the mean of its divisors is an integer number (1302891).

2^2605781 is an apocalyptic number.

It is an amenable number.

2605781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2605781 is an equidigital number, since it uses as much as digits as its factorization.

2605781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 2605781 is about 1614.2431663166. The cubic root of 2605781 is about 137.6087250248.

The spelling of 2605781 in words is "two million, six hundred five thousand, seven hundred eighty-one".