2109421 has 2 divisors, whose sum is σ = 2109422. Its totient is φ = 2109420.

The previous prime is 2109403. The next prime is 2109449. The reversal of 2109421 is 1249012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1653796 + 455625 = 1286^2 + 675^2 .

It is a cyclic number.

It is not a de Polignac number, because 2109421 - 2⁷ = 2109293 is a prime.

It is a Chen 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 (2109461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1054710 + 1054711.

It is an arithmetic number, because the mean of its divisors is an integer number (1054711).

2^2109421 is an apocalyptic number.

It is an amenable number.

2109421 is a deficient number, since it is larger than the sum of its proper divisors (1).

2109421 is an equidigital number, since it uses as much as digits as its factorization.

2109421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 2109421 is about 1452.3845909400. The cubic root of 2109421 is about 128.2491282475.

It can be divided in two parts, 21094 and 21, that added together give a triangular number (21115 = T₂₀₅).

The spelling of 2109421 in words is "two million, one hundred nine thousand, four hundred twenty-one".