1816261 has 2 divisors, whose sum is σ = 1816262. Its totient is φ = 1816260.

The previous prime is 1816253. The next prime is 1816271. The reversal of 1816261 is 1626181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1425636 + 390625 = 1194^2 + 625^2 .

It is an emirp because it is prime and its reverse (1626181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1816261 - 2³ = 1816253 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 (1816211) 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, 908130 + 908131.

It is an arithmetic number, because the mean of its divisors is an integer number (908131).

2^1816261 is an apocalyptic number.

It is an amenable number.

1816261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1816261 is an equidigital number, since it uses as much as digits as its factorization.

1816261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 25.

The square root of 1816261 is about 1347.6872782660. The cubic root of 1816261 is about 122.0092486046.

The spelling of 1816261 in words is "one million, eight hundred sixteen thousand, two hundred sixty-one".