1993861 has 2 divisors, whose sum is σ = 1993862. Its totient is φ = 1993860.

The previous prime is 1993829. The next prime is 1993877. The reversal of 1993861 is 1683991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1943236 + 50625 = 1394^2 + 225^2 .

It is a cyclic number.

It is not a de Polignac number, because 1993861 - 2⁵ = 1993829 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1993861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1993261) 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, 996930 + 996931.

It is an arithmetic number, because the mean of its divisors is an integer number (996931).

2^1993861 is an apocalyptic number.

It is an amenable number.

1993861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1993861 is an equidigital number, since it uses as much as digits as its factorization.

1993861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 37.

The square root of 1993861 is about 1412.0414299871. The cubic root of 1993861 is about 125.8630619447.

The spelling of 1993861 in words is "one million, nine hundred ninety-three thousand, eight hundred sixty-one".