1806421 has 2 divisors, whose sum is σ = 1806422. Its totient is φ = 1806420.

The previous prime is 1806407. The next prime is 1806461. The reversal of 1806421 is 1246081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1102500 + 703921 = 1050^2 + 839^2 .

It is an emirp because it is prime and its reverse (1246081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1806421 - 2¹⁹ = 1282133 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1806392 and 1806401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1806461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 903210 + 903211.

It is an arithmetic number, because the mean of its divisors is an integer number (903211).

2^1806421 is an apocalyptic number.

It is an amenable number.

1806421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1806421 is an equidigital number, since it uses as much as digits as its factorization.

1806421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 1806421 is about 1344.0316216518. The cubic root of 1806421 is about 121.7885120335.

The spelling of 1806421 in words is "one million, eight hundred six thousand, four hundred twenty-one".