6647601621 has 4 divisors (see below), whose sum is σ = 8863468832. Its totient is φ = 4431734412.

The previous prime is 6647601619. The next prime is 6647601643. The reversal of 6647601621 is 1261067466.

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.

It is not a de Polignac number, because 6647601621 - 2¹ = 6647601619 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6647601621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6647600621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1107933601 + ... + 1107933606.

It is an arithmetic number, because the mean of its divisors is an integer number (2215867208).

Almost surely, 2^6647601621 is an apocalyptic number.

It is an amenable number.

6647601621 is a deficient number, since it is larger than the sum of its proper divisors (2215867211).

6647601621 is a wasteful number, since it uses less digits than its factorization.

6647601621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2215867210.

The product of its (nonzero) digits is 72576, while the sum is 39.

The square root of 6647601621 is about 81532.8254201950. The cubic root of 6647601621 is about 1880.2762553334.

The spelling of 6647601621 in words is "six billion, six hundred forty-seven million, six hundred one thousand, six hundred twenty-one".