3581721643 has 4 divisors (see below), whose sum is σ = 3582085248. Its totient is φ = 3581358040.

The previous prime is 3581721641. The next prime is 3581721707. The reversal of 3581721643 is 3461271853.

3581721643 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3461271853 = 13 ⋅266251681.

It is a cyclic number.

It is not a de Polignac number, because 3581721643 - 2¹ = 3581721641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3581721596 and 3581721605.

It is not an unprimeable number, because it can be changed into a prime (3581721641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166603 + ... + 186868.

It is an arithmetic number, because the mean of its divisors is an integer number (895521312).

Almost surely, 2^3581721643 is an apocalyptic number.

3581721643 is a deficient number, since it is larger than the sum of its proper divisors (363605).

3581721643 is a wasteful number, since it uses less digits than its factorization.

3581721643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363604.

The product of its digits is 120960, while the sum is 40.

The square root of 3581721643 is about 59847.4865219919. The cubic root of 3581721643 is about 1530.0205962170.

The spelling of 3581721643 in words is "three billion, five hundred eighty-one million, seven hundred twenty-one thousand, six hundred forty-three".