1871021 has 2 divisors, whose sum is σ = 1871022. Its totient is φ = 1871020.

The previous prime is 1871017. The next prime is 1871029. The reversal of 1871021 is 1201781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1590121 + 280900 = 1261^2 + 530^2 .

It is a cyclic number.

It is not a de Polignac number, because 1871021 - 2² = 1871017 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1870984 and 1871002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1871029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 935510 + 935511.

It is an arithmetic number, because the mean of its divisors is an integer number (935511).

2^1871021 is an apocalyptic number.

It is an amenable number.

1871021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1871021 is an equidigital number, since it uses as much as digits as its factorization.

1871021 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 20.

The square root of 1871021 is about 1367.8526967477. The cubic root of 1871021 is about 123.2233147603.

The spelling of 1871021 in words is "one million, eight hundred seventy-one thousand, twenty-one".