1813421 has 2 divisors, whose sum is σ = 1813422. Its totient is φ = 1813420.

The previous prime is 1813391. The next prime is 1813429. The reversal of 1813421 is 1243181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1768900 + 44521 = 1330^2 + 211^2 .

It is an emirp because it is prime and its reverse (1243181) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1813421 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1813393 and 1813402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1813429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 906710 + 906711.

It is an arithmetic number, because the mean of its divisors is an integer number (906711).

2^1813421 is an apocalyptic number.

It is an amenable number.

1813421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1813421 is an equidigital number, since it uses as much as digits as its factorization.

1813421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 20.

The square root of 1813421 is about 1346.6332091553. The cubic root of 1813421 is about 121.9456220979.

The spelling of 1813421 in words is "one million, eight hundred thirteen thousand, four hundred twenty-one".