1810421 has 2 divisors, whose sum is σ = 1810422. Its totient is φ = 1810420.

The previous prime is 1810409. The next prime is 1810423. The reversal of 1810421 is 1240181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1020100 + 790321 = 1010^2 + 889^2 .

It is an emirp because it is prime and its reverse (1240181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1810421 - 2⁶ = 1810357 is a prime.

It is a Sophie Germain prime.

Together with 1810423, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1810421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1810423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 905210 + 905211.

It is an arithmetic number, because the mean of its divisors is an integer number (905211).

2^1810421 is an apocalyptic number.

It is an amenable number.

1810421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1810421 is an equidigital number, since it uses as much as digits as its factorization.

1810421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 1810421 is about 1345.5188590280. The cubic root of 1810421 is about 121.8783388084.

It can be divided in two parts, 18 and 10421, that multiplied together give a triangular number (187578 = T₆₁₂).

The spelling of 1810421 in words is "one million, eight hundred ten thousand, four hundred twenty-one".