1909021 has 2 divisors, whose sum is σ = 1909022. Its totient is φ = 1909020.

The previous prime is 1909003. The next prime is 1909027. The reversal of 1909021 is 1209091.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1863225 + 45796 = 1365^2 + 214^2 .

It is a cyclic number.

It is not a de Polignac number, because 1909021 - 2⁵ = 1908989 is a prime.

It is a super-2 number, since 2×1909021² = 7288722356882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1908983 and 1909001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1909027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 954510 + 954511.

It is an arithmetic number, because the mean of its divisors is an integer number (954511).

2^1909021 is an apocalyptic number.

It is an amenable number.

1909021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1909021 is an equidigital number, since it uses as much as digits as its factorization.

1909021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 22.

The square root of 1909021 is about 1381.6732609412. The cubic root of 1909021 is about 124.0519423387.

The spelling of 1909021 in words is "one million, nine hundred nine thousand, twenty-one".