1665444001 has 4 divisors (see below), whose sum is σ = 1793555092. Its totient is φ = 1537332912.

The previous prime is 1665443999. The next prime is 1665444017. The reversal of 1665444001 is 1004445661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 289034001 + 1376410000 = 17001^2 + 37100^2 .

It is a cyclic number.

It is not a de Polignac number, because 1665444001 - 2¹ = 1665443999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1665444071) 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, 64055526 + ... + 64055551.

It is an arithmetic number, because the mean of its divisors is an integer number (448388773).

Almost surely, 2^1665444001 is an apocalyptic number.

It is an amenable number.

1665444001 is a deficient number, since it is larger than the sum of its proper divisors (128111091).

1665444001 is a wasteful number, since it uses less digits than its factorization.

1665444001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128111090.

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 1665444001 is about 40809.8517640042. The cubic root of 1665444001 is about 1185.3411044830.

Adding to 1665444001 its reverse (1004445661), we get a palindrome (2669889662).

The spelling of 1665444001 in words is "one billion, six hundred sixty-five million, four hundred forty-four thousand, one".