1661203 has 4 divisors (see below), whose sum is σ = 1669288. Its totient is φ = 1653120.

The previous prime is 1661173. The next prime is 1661237. The reversal of 1661203 is 3021661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3021661 = 151 ⋅20011.

It is a cyclic number.

It is not a de Polignac number, because 1661203 - 2⁹ = 1660691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661243) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3726 + ... + 4147.

It is an arithmetic number, because the mean of its divisors is an integer number (417322).

2^1661203 is an apocalyptic number.

1661203 is a deficient number, since it is larger than the sum of its proper divisors (8085).

1661203 is an equidigital number, since it uses as much as digits as its factorization.

1661203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8084.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 1661203 is about 1288.8766426621. The cubic root of 1661203 is about 118.4334104565.

Adding to 1661203 its reverse (3021661), we get a palindrome (4682864).

It can be divided in two parts, 166 and 1203, that added together give a square (1369 = 37²).

The spelling of 1661203 in words is "one million, six hundred sixty-one thousand, two hundred three".