2191993 has 2 divisors, whose sum is σ = 2191994. Its totient is φ = 2191992.

The previous prime is 2191967. The next prime is 2192009. The reversal of 2191993 is 3991912.

2191993 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1669264 + 522729 = 1292^2 + 723^2 .

It is a cyclic number.

It is not a de Polignac number, because 2191993 - 2¹⁷ = 2060921 is a prime.

2191993 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (2191193) 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, 1095996 + 1095997.

It is an arithmetic number, because the mean of its divisors is an integer number (1095997).

2^2191993 is an apocalyptic number.

It is an amenable number.

2191993 is a deficient number, since it is larger than the sum of its proper divisors (1).

2191993 is an equidigital number, since it uses as much as digits as its factorization.

2191993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4374, while the sum is 34.

The square root of 2191993 is about 1480.5380778622. The cubic root of 2191993 is about 129.9011674852.

The spelling of 2191993 in words is "two million, one hundred ninety-one thousand, nine hundred ninety-three".