1661443203 has 16 divisors (see below), whose sum is σ = 2641798656. Its totient is φ = 908117760.

The previous prime is 1661443193. The next prime is 1661443211. The reversal of 1661443203 is 3023441661.

It is not a de Polignac number, because 1661443203 - 2⁴ = 1661443187 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1661443213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1719438 + ... + 1720403.

It is an arithmetic number, because the mean of its divisors is an integer number (165112416).

Almost surely, 2^1661443203 is an apocalyptic number.

1661443203 is a deficient number, since it is larger than the sum of its proper divisors (980355453).

1661443203 is a wasteful number, since it uses less digits than its factorization.

1661443203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3439874.

The product of its (nonzero) digits is 10368, while the sum is 30.

The square root of 1661443203 is about 40760.8047393571. The cubic root of 1661443203 is about 1184.3911850653.

Adding to 1661443203 its reverse (3023441661), we get a palindrome (4684884864).

The spelling of 1661443203 in words is "one billion, six hundred sixty-one million, four hundred forty-three thousand, two hundred three".