3665600021 has 4 divisors (see below), whose sum is σ = 3665721600. Its totient is φ = 3665478444.

The previous prime is 3665600009. The next prime is 3665600041. The reversal of 3665600021 is 1200065663.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 3665600021 - 2³⁰ = 2591858197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3665600041) 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, 22220 + ... + 88458.

It is an arithmetic number, because the mean of its divisors is an integer number (916430400).

Almost surely, 2^3665600021 is an apocalyptic number.

It is an amenable number.

3665600021 is a deficient number, since it is larger than the sum of its proper divisors (121579).

3665600021 is an equidigital number, since it uses as much as digits as its factorization.

3665600021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121578.

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 3665600021 is about 60544.1989046019. The cubic root of 3665600021 is about 1541.8721287958.

Adding to 3665600021 its reverse (1200065663), we get a palindrome (4865665684).

The spelling of 3665600021 in words is "three billion, six hundred sixty-five million, six hundred thousand, twenty-one".