1856021 has 2 divisors, whose sum is σ = 1856022. Its totient is φ = 1856020.

The previous prime is 1856017. The next prime is 1856027. The reversal of 1856021 is 1206581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1276900 + 579121 = 1130^2 + 761^2 .

It is an emirp because it is prime and its reverse (1206581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1856021 - 2² = 1856017 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1856027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 928010 + 928011.

It is an arithmetic number, because the mean of its divisors is an integer number (928011).

2^1856021 is an apocalyptic number.

It is an amenable number.

1856021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1856021 is an equidigital number, since it uses as much as digits as its factorization.

1856021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 1856021 is about 1362.3586165177. The cubic root of 1856021 is about 122.8931365218.

It can be divided in two parts, 18560 and 21, that added together give a palindrome (18581).

The spelling of 1856021 in words is "one million, eight hundred fifty-six thousand, twenty-one".