1021861 has 2 divisors, whose sum is σ = 1021862. Its totient is φ = 1021860.

The previous prime is 1021849. The next prime is 1021879. The reversal of 1021861 is 1681201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 540225 + 481636 = 735^2 + 694^2 .

It is an emirp because it is prime and its reverse (1681201) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1021861 - 2¹⁷ = 890789 is a 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 (1021831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510930 + 510931.

It is an arithmetic number, because the mean of its divisors is an integer number (510931).

2^1021861 is an apocalyptic number.

It is an amenable number.

1021861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021861 is an equidigital number, since it uses as much as digits as its factorization.

1021861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 19.

The square root of 1021861 is about 1010.8714062629. The cubic root of 1021861 is about 100.7234535284.

The spelling of 1021861 in words is "one million, twenty-one thousand, eight hundred sixty-one".