1870021 has 2 divisors, whose sum is σ = 1870022. Its totient is φ = 1870020.

The previous prime is 1870019. The next prime is 1870049. The reversal of 1870021 is 1200781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1653796 + 216225 = 1286^2 + 465^2 .

It is a cyclic number.

It is not a de Polignac number, because 1870021 - 2¹ = 1870019 is a prime.

Together with 1870019, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1871021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 935010 + 935011.

It is an arithmetic number, because the mean of its divisors is an integer number (935011).

2^1870021 is an apocalyptic number.

It is an amenable number.

1870021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1870021 is an equidigital number, since it uses as much as digits as its factorization.

1870021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 1870021 is about 1367.4871114566. The cubic root of 1870021 is about 123.2013578939.

It can be divided in two parts, 18700 and 21, that added together give a triangular number (18721 = T₁₉₃).

The spelling of 1870021 in words is "one million, eight hundred seventy thousand, twenty-one".