1993661 has 2 divisors, whose sum is σ = 1993662. Its totient is φ = 1993660.

The previous prime is 1993657. The next prime is 1993679. The reversal of 1993661 is 1663991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1674436 + 319225 = 1294^2 + 565^2 .

It is a cyclic number.

It is not a de Polignac number, because 1993661 - 2² = 1993657 is a prime.

It is a Sophie Germain 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 (1993601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 996830 + 996831.

It is an arithmetic number, because the mean of its divisors is an integer number (996831).

2^1993661 is an apocalyptic number.

It is an amenable number.

1993661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1993661 is an equidigital number, since it uses as much as digits as its factorization.

1993661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8748, while the sum is 35.

The square root of 1993661 is about 1411.9706087593. The cubic root of 1993661 is about 125.8588534510.

The spelling of 1993661 in words is "one million, nine hundred ninety-three thousand, six hundred sixty-one".