1661243 has 2 divisors, whose sum is σ = 1661244. Its totient is φ = 1661242.

The previous prime is 1661237. The next prime is 1661249. The reversal of 1661243 is 3421661.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (1661237) and next prime (1661249).

It is an emirp because it is prime and its reverse (3421661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661243 is a prime.

It is not a weakly prime, because it can be changed into another prime (1661249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830621 + 830622.

It is an arithmetic number, because the mean of its divisors is an integer number (830622).

2^1661243 is an apocalyptic number.

1661243 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661243 is an equidigital number, since it uses as much as digits as its factorization.

1661243 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 23.

The square root of 1661243 is about 1288.8921599575. The cubic root of 1661243 is about 118.4343610324.

The spelling of 1661243 in words is "one million, six hundred sixty-one thousand, two hundred forty-three".