2686781 has 2 divisors, whose sum is σ = 2686782. Its totient is φ = 2686780.

The previous prime is 2686777. The next prime is 2686787. The reversal of 2686781 is 1876862.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1666681 + 1020100 = 1291^2 + 1010^2 .

It is a cyclic number.

It is not a de Polignac number, because 2686781 - 2² = 2686777 is a prime.

It is a super-2 number, since 2×2686781² = 14437584283922, 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 (2686787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1343390 + 1343391.

It is an arithmetic number, because the mean of its divisors is an integer number (1343391).

2^2686781 is an apocalyptic number.

It is an amenable number.

2686781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2686781 is an equidigital number, since it uses as much as digits as its factorization.

2686781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 38.

The square root of 2686781 is about 1639.1403234623. The cubic root of 2686781 is about 139.0200443809.

The spelling of 2686781 in words is "two million, six hundred eighty-six thousand, seven hundred eighty-one".