6728620921 has 8 divisors (see below), whose sum is σ = 7460647488. Its totient is φ = 6016650000.

The previous prime is 6728620901. The next prime is 6728620931. The reversal of 6728620921 is 1290268276.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6728620921 - 2⁷ = 6728620793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6728620901) 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 7 ways as a sum of consecutive naturals, for example, 5013205 + ... + 5014546.

It is an arithmetic number, because the mean of its divisors is an integer number (932580936).

Almost surely, 2^6728620921 is an apocalyptic number.

6728620921 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

6728620921 is a deficient number, since it is larger than the sum of its proper divisors (732026567).

6728620921 is a wasteful number, since it uses less digits than its factorization.

6728620921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10027823.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 6728620921 is about 82028.1715083300. The cubic root of 6728620921 is about 1887.8842089443.

The spelling of 6728620921 in words is "six billion, seven hundred twenty-eight million, six hundred twenty thousand, nine hundred twenty-one".