1661503 has 2 divisors, whose sum is σ = 1661504. Its totient is φ = 1661502.

The previous prime is 1661489. The next prime is 1661519. The reversal of 1661503 is 3051661.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661503 is a prime.

1661503 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1661003) 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, 830751 + 830752.

It is an arithmetic number, because the mean of its divisors is an integer number (830752).

2^1661503 is an apocalyptic number.

1661503 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661503 is an equidigital number, since it uses as much as digits as its factorization.

1661503 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 1661503 is about 1288.9930178244. The cubic root of 1661503 is about 118.4405394035.

The spelling of 1661503 in words is "one million, six hundred sixty-one thousand, five hundred three".