1665121204 has 6 divisors (see below), whose sum is σ = 2913962114. Its totient is φ = 832560600.

The previous prime is 1665121201. The next prime is 1665121223. The reversal of 1665121204 is 4021215661.

It can be written as a sum of positive squares in only one way, i.e., 1548265104 + 116856100 = 39348^2 + 10810^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665121201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 208140147 + ... + 208140154.

Almost surely, 2^1665121204 is an apocalyptic number.

It is an amenable number.

1665121204 is a deficient number, since it is larger than the sum of its proper divisors (1248840910).

1665121204 is a wasteful number, since it uses less digits than its factorization.

1665121204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 416280305 (or 416280303 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 1665121204 is about 40805.8966817297. The cubic root of 1665121204 is about 1185.2645184445.

Adding to 1665121204 its reverse (4021215661), we get a palindrome (5686336865).

The spelling of 1665121204 in words is "one billion, six hundred sixty-five million, one hundred twenty-one thousand, two hundred four".